I took two pregnancy tests.. The first one came back positive but it had a very faint line. I took a second one about 4 days later- it came back negative. I was due to get my period on thursday- so its four days later right now. I just had my first baby in March and my period has been just as it was before her.... it comes every 21 days..... its like clock-work. It has never been later even under stress. I have been feeling very tired the past 2weeks or so, craving different foods-- alot of things like in my first pregnancy. Could the 2 different brands of tests i took have different sensitivities? Or maybe im just not far along yet to really register.
can anyone please help!

Thanks!