ocd problem

i have hiv anxiety which is gonna to serious everyday for me. i cant do sex with any lady because hiv in my mind. when i do sex with lady then always it comes in mind that may be lady get hiv doesnt matter i wear condom or not. sometime i discharge soon or sometime my penis dont erect because the fera of hiv. i wanna be remove this anxiety pls help me.my mind say everygirl got a hiv in this world does matter where i met to girl. sometime i scare to touch to girl now everything is happing wid me very bad i am 25 i have never sex wid lady but i got oppurtunities to have a sex with lady but when i be close with lady but hiv fear in my mind then my penis didnt erect properly. this is my problem pls tell me what should i do. doctor told me this ocd . he also told me i have to do expusers like i have to do sex with lady what  ever anxirty coming is coming i have to try to remove from my mind. pls help me i am oo stress