Pregnant? Infection?

My period is 2 days late. Going on 3. Normally I wouldn’t freak out. But on thursday I started spotting. It was brownish/pink and wouldn’t fill up my tampon. I decided to take the tampon out and i didn’t put one back in until friday morning before work. Same thing on it. Once again thinking theres not enough for a tampon, i took it out. I haven’t put a tampon in since then and have had no blood at all. Now I’m having super heavy discharge. Ive had light cramps on and off for about a week. No other symptoms except moody and headaches. Does anyone know what this could be?! I want to wait untl a week after my missed period to test