Unprotected coitus with a sex worker.

Around 2 weeks ago, I had unprotected vaginal intercourse with a sex worker twice on the same day within a period of 2 hours. Prior to that, I've only had 1 healthy sexual partner. The sex worker told me that she was healthy and gets tested frequently so there will be no complications. I couldn't think straight at that time and hence proceeded without protection. Since then I am extremely paranoid about contracting an incurable STD or STI. Around 2 days ago I noticed some white formation on my penis, upon consulting with a dermatologist it turns out it's just a yeast infection. But now my anxiety and paranoia is through the roof. I can't sleep and this is all I can think about. Please tell me when can I get tested and which tests I should undergo so I can put my mind to ease. I read that there's a window period of 3 months for accurate results. I'm only 21 and I made a mistake. Please help!