Help please

So i started with small cramps and then i had brown discharge and I didn’t think anything of it cause my period was supposed to come. When i would wipe it was very light pink (the brown discharge was not heavy at all pantyliners were just fine I didn’t need a pad) the discharge lasted 2-3 days the most... i started freaking out because i saw that it stoped and I’ve been extremely emotional EVERYTHING gets to me but im mostly scared that what if im pregnant.. I literally started my laster treatment today! Im definitely buying a test tomorrow for sure! I just can’t sleep cause it’s in my head!