I've Been Having Brown Spotting For A Couple Weeks. Period

I've been having brown spotting for a couple weeks. Period is due any day. I recently had the flu, and tested for pregnant the day after. Was dehydrated. It was positive. Took another test an hour later and negative. The next afternoon tested and negative. Did dehydration cause me to test positive early? Then after voiding and rehydration hcg wasn't high enough so I tested negative? My last cycle was 35 days, I'm on day 33 now.