Is it normal to get a short period?

Hi.. I was just wondering if I am crazy or not. I had slight cramps about a week and a half before I got my period this month. I never get cramps unless its about to come any min. I got my period the day it should of came, the first day it was brown and light, the following day it looked to be discharge with watery blood. The day after it was brown and light again. For two days after I had a little pink discharge. My period last for 4 to 5 days with a 31 day cycle. any thoughts? I am asking bc at the age 18 my obgyn told me I was sterile due to my BC. Its been almost 5 years since he told me this. I really do not want to take a HPT if not needed... Its heart breaking for me ... And my fiance.. I just need a little advice.. Plz