Does Oral Sex Lead To STD?

hello dr. in fact i think a stupid question, but i like you to answer me. before 5 months i had a girlfriend, i had kisses with here , but no intercourse, just kisses , touching, and once i had a stick of her pin (she put it on her clothes sometimes), and she kissed me many times on my hands while i had a dry hands(maybe some very small sores on it). i was afraid if saliva can transmit through this small sores. the funny thing that she is tested for hiv and she is negative and by the way , im registered nurse and i know alot about stds. i think that i have obsessive compulsive disorder, because every time i feel something i think its STD, or HIV , or any bad disease. i had some itchy skin , redness itchy and go with in minutes, , i felt like some hair follicles are little elevated, and i have to be honest , i was soooo stressed . i had some cold sores in my mouth, and i feel sometimes my ear is hot, i had chronic sinusitis. i thought that any skin disease can be spread easily , i thought maybe i got herpes or fungal or any thing like that. i asked a doctor and he told me that im very obsessed. please any one help me in that????