HIV exposure to less than 5 seconds unprotected anal insertion (worried sick)?

Is it possible to contract any sexual diseases (HIV/STD) through a one brief encounter of unprotected anal insertion? It was an uncalled for situation and the penis was inserted for less than 5 seconds before I pushed it out. There was no precum or *** at all. Should i be worrying like mad as i am just because i'm not sure about how "clean" he is? And this experience was my first encounter which i deeply regret. Other than that, I had no intention of a sexual intercourse. I have been worried sick and have not been sleeping for days, somebody, please assure me and give me the truth. Thank you.