symptoms of pregnancy

I am on the Depo-Provera shot, but they have changed the formula to a lower dose of hormone, and the last shot I got was the first one of the new type, two months ago. Before, for almost 2 years I've been on the shot, I would constantly spot. Since the new shot, I've spotted one time, had extreme breast tenderness, digestive issues, moodiness, and darker/stronger urine. I took one pregnancy test and it was negative, but I'm still wondering... If anyone can help, please do! Thanks so much

The symptoms may be due to the change in hormonal levels??!!??