16dpo - AF or is something else happening?

Jackie
Hi- I'm hoping someone can shed some light on my situation if any similar experiences have been had out there. My husband and I just started TTC last month. I'm 34yo and healthy with typically normal periods every month. I am now 16dpo and was of course hoping to be pregnant. I took 3 tests (mostly too early) and 1 today all of which came out negative :( I had what I really believe was implantation bleeding at about 10dpo and it went away after 2 days. I also experienced symptoms like really sore breasts and itchy nipples, heightened sense of smell, naseau, headaches (which I never get) and more. But two nights ago I started having pretty serious cramping and the next morning when my AF would be expected, I had a pretty consistent flow of bright red blood with clots and more cramping (unusual for me) and it lasted all day. Now today, stopped bleeding altogether. Could this be AF acting funky for some reason even though I'm very regular and don't ever see the bright red stuff? Is there no chance I am pregnant? 😔 Should I see my doctor even though today I feel fine so far? I feel clueless. Any advice?