I was on my fourth day of my first shot of depo yesturday and my boyfriend ejaculated in me am i pregnant?

Was this your first ever depo shot? Many OBGYN's suggest you use backup BC for the first month on birth control. It takes time for the depo to prevent egg release in a reliable way. If you did not use any other form of BC for this event you may be at risk of pregnancy.

If your shot occurred a week or less after the start of your last period, then you are already protected. Otherwise, you may be at risk for pregnancy.