Spotting for 6 days and now 1-2 days late

So my period was due Thursday or Friday (August 3 or 4) , I started spotting Monday (July 31) had bright red blood for a couple minutes then to light spotting brown until Wednesday evening when I started bright red again, thought for sure my period was starting, Thursday morning I got up and the same so thought ok AF is here. I put on a tampon and went on, shortly later I took it out and there was a small clot, nothing else on it, I changed it and later when I took it out nothing was on it. Since then I'm still just spotting brown. I don't have cramps or tender breast like I usually do, just bloating. I'm just worried, I don't think I'm pregnant because of the bright blood but don't understand why AF isn't showing like usual. Help please? Anyone?