Could infection be causing these problems?

Patient: I started my period on the 13th of November, I got off on the 17th ( I am a 28-30 day girl) I had unprotected sex on the 19th. I went to the doctor the other day and I have a bladder infection I am now on Nitrofurantoin 100 mg and UTA capsules. Could having the unprotected sex cause the bladder infection? I have had a headache for almost three days now it comes and goes, for the past three nights I am getting nauseous and lightheaded. Could the infection be causing these symptoms or could I be pregnant? I havent started my period yet but, I am starting to have my symptoms like face breaking out, moodiness, cramps etc. Or could these symptoms be from pregnancy? I would only be 4 weeks if I were to pregnant ( I hope not though )

Doctor: It seems unlikely that you may be pregnant especially taking into consideration the timing of the sexual encounter. I wo uld however advice you to do a home pregnancy test test just to be sure.Having unprotected sex can definitely lead to a urinary tract infection. Due the a short urethra in females, it is easier for infection to travel up into the bladder. My advice would be to avoid sex until the infection heals.