I had an unexpected counter with a tranny/crossdresser

Well before i ask i just want to give a little background on myself about two months ago i found out that i got diagnosed with malt lyphoma and that it was life threatening. After i heard about this i started to get really depressed and looked to drugs and alcohol to ease my pain. So one day i was feeling sexually frustrated or horny like all normal teenage boys are and i looked online to try and find someone to meet. i found this older women who looked very attractive and i set out to go see her and while i did this i was very drunk and probablly wasnt the smartest thing to do but i guess i was just trying to get a lil loose. i finally arived at her place and as soon as i came in we got right to buisness . im not going to get really descriptive here but all she did was perform oral sex on me. i left feeling better and a little relieved and feeling good that i did something with a older women. About two days later i go to craigslist to find someone else but i see something under her ad saying "t4m" and right there and then i paused and just stared at the computer screen for what seemed like an eternity. I felt so ashamed of myself. I thought how didnt i notice? Am i gay? . I had to come to terms that i basically did a sexual act with a 40 year old man. I started to go crazy and distanced myself from alot of people and its been on my mind these past couple months constantly. Im scared that she will try to come and find me and tell people what happened. I mean she only has my phone number thats it she doesnt know my name. Does this experience make me gay? How should i try to cope with this problem? please i just need guidance during this dark time in my life