Hi and welcome to Anxiety Zone,
Thinking about HIV and thinking about getting tested is known to cause people anxiety. And anxiety can have really strong effects on the body causing all sorts of things like the things you listed. Also, keep in mind that if you recently took that other med, your body may be recuperating from that mild reaction to that med you took, and sometimes meds have temporary side effects. I think, be patient with your body right now and give it some leeway to be a little off until you feel more relaxed.
As far as HIV goes, I believe people should always be safe and use safe practices, but the truth is that it can be pretty rare to transmit depending specifics of the incident and who is involved. Its good to get tested I think if you've been involved in unprotected sex, but even so, just because a person has had unprotected sex does not mean they are likely to acquire the virus. (and even people with the virus do not always pass it to a partner). I still always like to say people should be safe regardless of the stats, but I think its okay to consider better case scenarios if you begin to worry about an incidence of the past. Be on the safe side and get tested, but keep your mind as optimistic as possible because I think the stats support that.
I hope that I'm making sense there.
Your physical issues you are experiencing could totally be a combination of stress and the way the brain and body have this uncanny ability to create "symptoms" of the diseases we fear. Its almost like magic. The body will say, "Oh, he wants to worry about HIV? Well, now that I know this, and I've seen a google medical list of symptoms, I'm going to go all out and imitate it!

Just watch me work my magic. Its going to seem so real!" Sure, its okay to be on the safe side and get checked by a doctor, also for peace of mind, but do be suspicious of the body's "magical" ability to create the symptoms we fear.
Give it some time. Keep us updated on how you are doing!
-Ravens Lady