[Harmony♥]

With birth control, it could fail at any time. Nothing is 100%, and when you have the birth control injections, the likelihood of them failing are higher. if you've been experiencing symptoms of being pregnant, the only way to know for sure is to take a pregnancy test. So, because you've engaged in sex, I'd say, yes there is a chance of pregnancy regardless of you being on birth control. Like I said, nothing is 100% (except for abstinence).

If your short on cash, you could always borrow money from someone with the promise to pay them back, but there is always ways you can get a pregnancy test done for free. Do a local search of free clinics in your area, or even go to the dollar store to purchase one of their tests. It's like just $1, and they are as accurate as name brand tests. This should be done before anything else.