Advice - So confused and Nauseous

My husband and I have been TTC for 5 months. In November, my cycle was much longer than usual and my fertile days were a lot longer according to the CB Advance OPKS.

I got what I think might have been my period the first week in December. But honestly, I’m second guessing that.. day 1 was spotting, day 2 was heavy, day 3 was medium, and then day 4&5 was spotting/light. Not typical of my periods usually there are 4 heavy days. And on the last day, I got so sick. Like left work early sick at my stomach. And ever since then, I have had waves of nausea and upset stomach. Never have thrown up. But am drained and nauseous.

The last 7 days I have had high fertility on OPKs. But haven’t hit a peak.

Before this “period”, I did have a faint positive on FRER. I’ve tested since and nothing.

Anyone else experience anything like this? I don’t know if I’m going crazy or not lol. Maybe it’s just a stomach bug. I’m just desperate to know if anyone has or is in a similar situation as me.