I bet y'all hear this a bunch

Ashton • Hyperthyroidism
My cycles are so unpredictable but the length is always clockwork. No fail my periods are 6 days long. In January I had no symptoms of it coming on and I bled normal/heavy two days. Barely two days. And February - nothing. I took a test a few days ago and it was negative  cause my fiancé was swearing I'm pregnant. Monday I started feeling dizzy and now I'm off-on dizzy all the time. Should I be taking another test soon? I felt like I'd know by now. 
Note: I used an $.88 test at Walmart. I'm not sure if they're really reliable but it was quick and cheap and it says 99% accurate. Not sure if that matters.