Could i be pregnant. i had my last depo shot on the 3rd of march. symptoms is period like pain, tender breasts, abdomen feels heavy but no period yet?

Yes: Depo-Provera is intended to be used/given/taken every 3 months to be effective as birth control. Your March 3rd injection would have run out around July 3rd (actually you get a few days leeway). So if you've engaged in unprotected sex since then, you could now be pregnant. Best way to find out if you're pregnant is to take home pregnancy test, which is readily available at most pharmacies.