Remember Stefan there are those who have walked where you are walking.
Not all His children suffer this experience of anguish.
He deals with each differently and knows what is best.
Probably everyone here at the BB who knows of your situation are supporting you in prayer.
True, as you have indicated there is the possibility of some who have never been saved (or doubting to that effect) going through this kind of experience.
Either way the savior has said. John 6:47 Verily, verily, I say unto you, He that believeth on me hath everlasting life.
John Bunyan (Pilgrim's Progress) was one of those people who being a believer was struck with the thoughts of his present tense sins.
He suffered fits of depression and doubt for several years before he was delivered.
He later said "I fell but I did not fall away".
In this case the "P" in TULIP is applicable.
Persevere in patience, He will deliver you.
For some deliverance comes suddenly:
Malachi 3:1 Behold, I will send my messenger, and he shall prepare the way before me: and the Lord, whom ye seek, shall suddenly come to his temple, even the messenger of the covenant, whom ye delight in: behold, he shall come, saith the LORD of hosts.
For others it is a slow process (like mine):
Proverbs 4:18 But the path of the just is as the shining light, that shineth more and more unto the perfect day.
HankD