ADVICE PLEASE 🙏

My boyfriend and I have been TTC since February, but so far no luck. My cycles have always been between 28-31 days long, and periods last about 3-5 days. Well my last period started July 9th, and was heavy-ish for about 4 days and then was incredibly light for another 5 days or so (like barely anything there, only when I wiped.

I am now 18 days late, and don’t know what to think! I’ve done 2 hpt and both negative, I’ve been to the doctors and had a negative urine test there, as well as a negative urine test from the lab they sent the sample to.

I’ve been having a lot of cramping on and off for a few weeks, but absolutely no sign of AF. Doctor did blood work (didn’t test for pregnancy through blood), but tested my hormones for PCOS, and tested my blood count and glucose which all came back normal.

Today I have been having this weird brown discharge (very small amount), and I just don’t know whether it’s my late August period, my next period super early, or if I may actually be pregnant!!

I’m very doubtful at this point that I am pregnant, but this is all so irregular for me so now I don’t know what to think!!!

Any opinions??????!!!!