Hi I have been off the depo shot for 4 month and me and my boyfriend have had unprotective sex many times yesterday I had pinkish discharge could I be pregnant

Yes, it's possible... but it's not the most likely cause. It could be due to other causes... irritation to the cervix from the frequent sex, or ovulation are just two possibilities. If you haven't resumed regular periods yet, and you might not for quite some time, all you can do is try a pregnancy test maybe once a month if you are no longer using birth control.

ANY time there is penile insertion, there is the risk of pregnancy. But if you had sex only yesterday it is highly unlikely that you are pregnant now. It takes time for the sperm to reach the uterus and they need to find an egg ready for fertilization.

So your discharge has nothing to do with pregnancy. That does not mean that you won't find yourself pregnant later. You just have to wait until your period is due and see whether it comes or not. That is the first physical sign that you are pregnant.

The typical time between shots is about 3-4 months. Have you had your second shot? Are you continuing with the depo. Honestly it sounds like you're coming down from the shot. You should schedule an appointment with your doctor to get your next injection.