Most early pregnancy symptoms are the same as PMS and also as some birth control/pregnancy medication. The only sure way to know is to wait and test.
The injection isnt 100% so take a test as these symtoms accour in most pregnancys
Take a pregnancy test when your period should be due. I know that the shot for birth control can cause your body to behave very strangely. But just to be on the safe side take a test.