Relationship issues. Overcome this pain!

During my third year of my college i experienced loads of anxiety and fear .i thought i was a transgender or gay .iam constantly checking through Google what is gay and what is trans .i have taken many online test .after one week i used to have thoughts that iam a psychopath . i thought that i will kill people without any reason . during that time i checked in Google what is psychopathy and taken many psychopathy tests nothing satisfied me .i consulted a psychiatrist i told my problems he daignosed me with ocd but after that i had thoughts like whether it is ocd or something else .i have gone through one year treatment .my situation was i my girlfriend broke up with me last year iam begging for her past ten months but she has lost trust in me .now iam getting thoughts like she likes other guy and having sex with that guy it gives me more pain , anxiety and fear .i have to overcome my breakup but i still love her a lot .i have forget her and look at my career .how to overcome this pain