Advice please! *tmi image*

Bit of a long read sorry ! My cycle is usually 36 days long, give or take a day. I tested a week after AF was due and BFN so Imfigured I probably wasn't pregnant and waited for AF to show. On day 8 of AF not showing I got a blood test that showed my HCG was at a level I wasn't considered pregnant, so I accepted it, then on day 9 of being late I got this spotting (pictured) there wasn't much of it, that happened through out day 10 too, mostly just the tip of a tampon, not much at all, then today and stringy piece of red blood came out so I figured my period was close but still tonight it's just light spotting and nothing more, I usually have quite heavy periods so this is odd for me, I'm off to the doctors office tomorrow but I'm wondering if anyone else has experienced anything like this and what was the outcome or what are people's thoughts? Thanks in advance! X