Just gotta get in there and do it man. Alternatively if you don’t love the gym anymore there are other things to do which will burn calories and burn off some steam... swimming, buy a Mtn bike, boxing/bjj.
or keep at the gym, you don’t have to start back into a 5 or 6 day routine like you finished on before you got injuried. Why not just aim to go twice a week and make them quality sessions. After a month increase it to 3 times a week and then to 4 and so on until you are going the amount you want. That’s the easy way to do it and will have less chance of failure.