I've been taking tri-sprintec (birth control pill)for almost 2 years now and have never had an issue with my period until last month. I was 4 days late starting and it only lasted a 3 days which is not normal. And so far this month I am going on 2 weeks late and my periods usually work like clock work always starting around the same time and lasting about a week. I have taken 3 test, 1st one came out invalid, 2nd one came out with a faint positive and the 3rd one came out negative. Also for the past week I've been waking up sick and going to bed sick and certain smells that never bothered me before just make me gag. Could I be pregnant?

Well there is never a false positive!
So try going to your doctor and getting a forsure reslut.
There is however a false negative, it doesn't detect a pregnany,
But if you said 2 times you have a faint line under positive,
I recoment going to the doctors and getting some blood work done.

Well there is never a false positive!
So try going to your doctor and getting a forsure reslut.
There is however a false negitive, it doesnt detect a pregnany,
but if you said 2 times you have a faint line under positive,
I recoment going to the doctors and getting some blood work done.

Actually, you're wrong. False positives can happen. They're not that common, but they are possible.