.. so he is not going to get another til april I know that sounds horrible but I can't help it... he was due in november and it hasnt hurt him yet...
Sorry, but, I'm still confused. Are you talking about the coggins being overdue and it hasn't hurt him yet? Or, the shot being over?
As far as giving the shot yourself. Have you ever done it before? There is a bit of science to it all. There is a triangular spot on the neck that you give it and to make sure you aren't in a spot where you draw blood back into the needle.
It's a little harder than you think it might be too. My horse had surgery years back and had to have shots given for awhile. My vet showed me and my husband how to give them. My husband did it usually and I decided to give it a try. I didn't know till I got it started that it was going to bother me. I had no idea! So, here my horse is with the needle only inserted shallowly and I knew I had to finish so I put the medicine in. It wasn't in far enough. Anyway, after that, I left it up to my hubby, bless his soul.
Either way, I advice you to have your vet there to teach you how and where.
After that if you feel you are comfortable with it, by all means give your own shots.
But, stay active with your vet in case of an emergency.