I have OCD but I am also a Christian and definitely not in that order. OCD is a hard thing to live with (impossible for me if I was not a Christian) and although you lost your faith, the Lord has not lost faith in you, He created you and although sin has corrupted His creation (we caused the corruption) and that opened the door to make it possible for humans to get mental disorders, it doesn't stop His love for you. (now I am going to get off topic) You see, the most important thing to God is not our happiness, He does want us to be happy, but it is not what He created us for, we were created to have fellowship and to be in a true relationship with the one true God of Creation and to bring glory to His holy name.
When man sinned that relationship was broken, because God is Holy, He by nature can not dwell where sin is, His nature of holiness must destroy and fight evil wherever it is, He must judge it and condemn it, because He is completely just and holy. All of us have sinned and because of this our situation is hopeless, we are destined to be in hell for all eternity because the Lord in His perfect nature must judge our sin. What I am trying to show is the exceeding sinfulness and evilness of sin.
This world we live in was created by a Holy Being (God), it is His universe, not ours, not the angels, it is His alone, we are granted the privilege of being born in it, He gives us breath, He give us family to enjoy, He gives us sunsets and the stars to look at, He gives us the chance to fall in love. But as you can see there are also problems (evil) in creation, God gave humans and angels free will and obviously we and some of the angels have used this free will to tun against the Holy God who we owe our existence to, we blaspheme His name, lie and slander people, murder and hate others, we do countless things to hurt the Lord.
But in His mercy He has not left us in this place of evil to die and to be lost forever, He has come down in the likeness of sinful man in the Person of Jesus Christ (who is very much God) to die on the cross and to take away the punishment and wrath of God that we so rightly deserve. "For God so loved the world that He gave His only begotten Son that whosoever believes in Him will not perish but have everlasting life" (John 3:16)
God the Father, the holy Creator sent His Son (who is Jesus the Son of God, the second Person of the Holy Trinity) to die for mankind, we have sinned against the Holy Lord and we will all one day give an account to Him for what we have done, but He has told us this in His holy Word:
17For God did not send His Son into the world to condemn the world, but that the world through Him might be saved.
18“He who believes in Him is not condemned; but he who does not believe is condemned already, because he has not believed in the name of the only begotten Son of God. (John)
We can be justified by faith in the Son of God but it is only by His grace that we are saved, Jesus loves you, more than you can know, don't blame Him for your illness, just thank Him for His salvation and love for you and receive His forgiveness, you have reason to be fearful of God because He is angry at you for your sin, but Jesus took this anger and wrath on the cross, believe in Him as your Divine Substitute that took your punishment and you will be saved.
This may not have been the response you expected but it is the one the Lord Jesus wanted you to hear, God bless, SoS.
One more thing, here are a few web pages that will help you:
http://net-burst.net/god/angry-at-god.htm
http://net-burst.net/guilty/scrupulosity.htm