What Causes Constant Tiredness After Having Unprotected Sex?

I got my period on the 26 of last month. My period only last 4days. I had unprotected sex right after my period. The last time I had sex was on the 7th of this month. Ive been really tired since then. All I want to do is sleep. I know it s to early to know if I m pregnant or not but idk what s wrong with me. Is it too soon to get pregnant??