Help!!!

Help! I'm 3 months postpartum. I did get my tubes tied during my csection but lately I've been feeling nauseous when I wake up on the morning and I've been more tired than normal. So I decided to take a pregnancy test. The first one I could have swore I saw a faint line but it never had color... I go back to look at it a few hours later and there's a second like that's pink !! I took another this morning and it was a negative bit again a few hours later there's another line ! I know they say test are invalid after a Certian amount of time but a negative for me has never turned positive! What do you guys think ???? ?!!!!