Well During Intercouse With My Boyfriend A Month Ago. After

Well during intercouse with my boyfriend a month ago. After having a round, we didnt wipe off his sperm, then after a few minutes he inserted it back. After a few minutes I started having irritations on my vagina. A few days after that I went on my periods. I went to the chemist a few weeks ago n they gave me an ointment, today when I consulted my doctor she just gave me some capsules and said I should come back after my periods, what do you think the problem is since well I am still having the irritations?