Been on the depo shot for 3 years have been off it since april 2018 no period yet but been having some nausea sore boobs , etc could i be pregnant ?

Maybe. Maybe not.: Can do a urine pregnancy test, which gives a reliable result 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and thus lead to a repeat test. If a woman gets her next normal regular period, then she is not pregnant and a test is not needed.