I had a unsafe sex 5 month ago and a two weeks ago i had strep throat and like month ago i have a small rash on the bottom of my back is that an hiv?

HIV is Hard to get: If you got HIV and got a full body rash two to three weeks after exposure then this would be a possible explanation. But, five months? Nope not likely. It is something else. Do not forget that if you have a high risk exposure to HIV you can prevent infection as long as you get on the post exposure prophylaxis" regimen within 72 hours. You should have a doctor who knows what to do.