im late on my period i have been having signs of pregnancy an gaining weight n pg test say negative

You should call a doctor asap, Ive heard of a few things that contribute to this. I dont want to alarm you for its pry not that big of a deal, but in some instances Ive heard late periods and wieght gaining (were talking like 20 lbs or more) headaches, nausia, and sometimes swelling is from forms of hepititus and or liver problems. Ive also heard of Cushings disease that is basicly high levels of cortsol in the blood caused by taking inflammatory or allergen drugs, coupled with high stress levels. Im not saying thats it, just something you might want to ask your doctor. Personally I'm hoping its just a bad pregnancy test. Good luck and prayers on your little bundle.