Little advise needed!

Hello everyone, well I am a little stressed which I shouldn't be well TTC, I am a tyoe 1 diabetic and my BG levels have been all over the place, sore nips, and a little bit of heavy feeling, I was suppose to start AF on 8/2, my cycles always run about 45 days, I bought a batch of pg test on ebay, cheapies, and I got a negative last week.Was it to early? Bad cheap test? In March i was late a few days and after the day i tested AF came. So the disappointment is crushing. What would you suggest, buy a different test just wait a few more days?