I had unprotect sex on 18 through the 20 and on the 11th of April through 18th and I'm am due for my shot like I was suppose to go on the 22nd of April and I didn't go

No form of birth control is 100% effective, even when used correctly. Skipping shots will greatly increase your chances of pregnancy.
The only way to know if you are pregnant will be to take a pregnancy test.

No you can't get pregnant but if you miss your shot it's a 50 50 chance

Yes, you can get pregnant on the depo shot. No form of birth control is 100% effective.