Helpful advice is greatly appreciated

I am on birth control but do not always take it as I should. Usually I am very regular give or take a day. Right now I am 2 and a half weeks late but this past cycle I had some irregular bleeding. I feel like I constantly need to eat. I've put on some weight in the last 3 weeks but I am also very bloated. It feels like I have a constant headache and fatigue and (unfortunatly for my fiance) have been rather short tempered. I know I should just take a test but I have felt like this before and the tests came back -. Is it possible to miscarry and still have all these symptoms?(My mother had a hard time keeping pregnancies) Is it possible to think you are pregnant and make these symptoms? I need advice desperately.