Tanisha,
There is a spiritual condition with a Latin name I can’t recall right now (similar to “acid” I think) which is also called, or related to, “scrupleousity”. (Both are also related to acute or chronic depression, and either may lead to the other.) We have had a number of people here who suffer from it, and your descriptions line up with it.
I say this because this spiritual affliction is not a sign you are not being saved from your sins, and not even that you are not in good standing with God despite how you feel. It’s the spiritual equivalent of a migraine, or it can be an attack from devils (Luthor called it being mugged by Satan!)
That isn’t going to help how you feel of course – if this is the problem. But those of us who suffer chronic depression, for various reasons (not all of them the same reason), often learn that the pain is easier to bear when we can understand it isn’t from several sorts of problems.
But it still hurts, and it is literally a physical pain, too: the same parts of our brains that suffer physical pain light up, and it can leave quite physical ‘scars’ (so to speak, not actually scars, but similar) in our neural paths.
It is also possible this is being inflicted on you by God (or through His authorization anyway if not directly), for being an unforgiving person of the sort you’ve been saying you were – and maybe still are.
I’m not going to say you should forgive yourself: I seriously doubt that’s anyone’s duty, and I know sometimes it’s hard to accept forgiveness, too (even though that is a duty). I would forgive you, if that would help, but you haven’t sinned against me, and I’m certainly not God to provide forgiveness for sins against other people.
But those of us who have been seriously unforgiving in our hearts, have often also gone through what you’re talking about; and we made it out okay on the other side, even though it felt at the time like we wouldn’t. I think God sometimes teaches us not to behave certain ways by inflicting on us the results of what we would inflict on other people, and that’s true for insisting on unforgiveness on other people, too. The scriptures talk about this on occasion.
So, my questions and/or recommendations:
1.) Are you accepting and cooperating with the pain? I don’t mean in the sense of hurting yourself – you shouldn’t do that – but in pouring the pain on your sins, spiritually. I can’t quite tell if you’re doing that or not, but if you aren’t then you should. Many people, myself included, are often helped by this exercise.
2.) Are you still holding unforgiveness in your heart against someone else? If they themselves haven’t repented yet, then such a forgiveness will necessarily be incomplete, but God expects and teaches us to prepare for their reconciliation. I get the impression you’re still suffering from this, though I hope I’m wrong. Even small steps in that direction, if so, can help. (So can pouring the pain on your sin, and the next thing, goo.)
3.) One of the problems of pain is that, even when medicinal, it tends to focus us on ourselves. That’s hard to avoid, under the circumstances! But like Sherman, I recommend you find something to do to help other people (or if somehow you can’t find other people to help, then help some animals; or if that’s somehow impossible, find people to pray for!) It may feel like you have no strength to give to that, but you may also find that putting what little strength you do have toward it will open up more strength.
Also, without getting into a critique of Calvinism and/or Arminianism: Calv logic of reprobation and election does not mean that those who fall away are necessarily of the non-elect, only that God has not yet led them to be true Christians. Personally I am not sure that Calvinist logic actually involves the persistence of the elect as Christians; what it does certainly involve, is the victorious and competent persistence of God in saving those He intends to save from their sins. (Which Arminians would say, includes all sinners! Universalists, such as ourselves, agree on both the scope and the persistence.)
But that is beside the point: what’s more important is that, if the Holy Spirit was not already leading you to do so, you would not be capable of any intention to be saved from your sins. So while other people might suppose you’re only faking about that, if you can see that that’s a legitimately true concern in your heart, then you can be sure the Spirit is operating in you with an eye toward your salvation from sin. Consequently, God will not give up on you. 
At worst, He’s burning up the straw and stubble you’ve built on Christ, the only foundation anyone can build anything on.
In fact, even if your pain is caused by other things, not by the specific intention of God (directly or indirectly brought into effect), God can and will still use your pain for that purpose.
And last of all, though perhaps I should say it is first of all: so far as you can, try to remember that God Himself voluntarily suffers with you, sharing the burden of your pain, which we see happening historically at one particular time and place on the cross, but which happens across all space and time. He suffers with the innocent victims of natural accident and unjust infliction; and He suffers with those whom He is punishing for their injustice, being reckoned with transgressors. Whatever your situation actually is, one or the other or some combination of both, look to Christ on the cross, bleeding with you, physically and spiritually.
God bring you peace and strength, and patience (in case the peace and strength come later rather than sooner).
)