Can i still be pregnant?

I went to my doctors and had a urine prego test done, it came back positive! But it was a very faint positive! My doctor then had me go and get a blood prego test done and that came out a negative! Both test were done on tha same day! But im not sure wich one to beleive? I still have prego symptoms! (tired alot, EXTREME thirst, frequent urination, bloating, and cramps like im gonna get ma period but no period! And they seem to go away when i drink water!) ma period is about a week late! Can i still be prego, and tha test is wrong, or is tha test right, and im just goin crazy? What should i do? Beleive tha blood test or have them redo both test? Any ideas will help? Thanx in advance!!