BC fail or no?

I started to feel a sharp pain on the left side of my pelvis, with a flutter feeling a couple of days before I was due for my depo shot. I figured it was just gas so I had my shot renewed on the 4th. The most symptoms I've had from the shot was a little diarea a day or two after which stopped after the second shot. This was my 5th. I've started to notice I'm having to pee more, I feel the need to eat even when I'm not hungry. I have had slight cramps but nothing major, slight nausea at random times that seems to be increasing in intensity throughout the day but not enough to make me run to the bathroom. My mucus seems thicker then it has been since I started the shot, it's usually watery but now it's more sticky. I'm always tired now, even after a good night's rest I feel the need to nap shortly after. I have noticed a full feeling in my pelvis as well, even after i poo or pee or release gas. I have taken 3 tests with fmu and all neg. I usually have random light bleeding throughout the 3 mths between shots but I haven't noticed any since I got it renewed. I've been on time with all my shots so I don't know how I could have become pregnant. Anyone have any other ideas?