Questionable

Hi ladies. Im ttc with baby #2. i have a regular cycle, 28 days lasts 5 days, like clock work. i ov'd apparently on the 17th, had sex a day before and the day after with SO. Earlier in the day on the 28th I was light headed and dizzy, that night I got really sick with diarrhea, vomiting, chills, and cramps. I thought I had experienced food poisoning but my family ate the exact same thing. To make things more confusing I started to spot this sane day as well and have on and off VERY lightly since then. Both pink and brown blood. I'm expected to start af tomorrow, if I continue to do spot like I am by tomorrow , when should I be in the clear to test?