Low hcg? All signs still neg??

I had a normal AF on Aug 17, I'm always regular and I have an app that keeps track. My cycle is about 24 days so when my September AF was supposed to arrive, nothing.. Roughly a week later I had some red to pink to brown discharge, it was super light which is not normal for me. I tested when Glow told me to but negative, I tested before I got the random red/pink discharge and I tested after that but all tests show negative.. My breasts have enlarged, nipples are very tender, darkened, and I've been bloated for 2 weeks now which is not normal for me at all. Also during my normal AF I have huge pains that only IB800's can take away and they're prescribed from my doctor.. This dischareh I had a week after I was late, had no pains at all.. What can this mean? Help please?