Have Food Poisoning, Fever, Diarrhea, Blood In Stool. What Is The Reason? STD?

Hi there, I am in my late 20s, and had potential exposures about 3.5 months ago- receptive oral and intercrural (between inner thighs) intercourses but nothing anal. I am homosexual and exclusively dating Caucasians above 55 years of age. Here are my symptoms so far: 1) 1.5 weeks after the last exposure: food-poisoning (or perhaps not) that resulted in vomitting, diarrhea and slight fever but made a speedy recovery after ~30 hours. 2) 2 months after the last exposure, I developed intermittent mild fever (oral temp 37.8C) that lasted till now. The fever doesn t last long, at most for 2 hours and in most cases, it comes and goes within 30 minutes (or just a few minutes), strangest fever I ve ever experienced; 3) 2 days ago, I developed diarrhea resulted in dark stool and slight blood . I have been very worried and anxious for the past 1 week, this is driving me mad.. Are these the classic symptoms of HIV? And many thanks in advance for tending to my message.