How do I cope with the loss of an animal?

I know it may sound stupid, but I had two baby squirrels for a couple of days after they fell out of a tree and I was feeding it every two hours and I became very attached to them both. My mom wasn't too happy with the idea of me being around an animal that can have many diseases, but she put up with it for a little while. Well my dog ended up getting a hold of one of them and it ended up dieing and as for the other one my mom decided to set it outside for that fact that it can be dangerous and very hard to take care of a wild animal, especially since neither one of has the time. But before that I had called many places and none of them would take it in to take care of it. Well, I finally found someone that would take it in but I got their voice mail so that's when she put it outside. Four hours later they called me back and were going to pick him up so I went outside looking for him thinking maybe he would still be alive and the ants had gotten to him. Now I just feel awful because I became so attached to both of them and was really determined to save their lives. I now feel like there was absolutely no point in taking them in in the first place. There was no point to it at all. I should have either left them their and hoped for the best(like the mother coming back) or I should have stood up for the squirrels and decided to keep them until I got a hold of someone that could take them. Now I have awful images of these two dead squirrels in my head that I could and should have saved. I just need advice on how to cope with this.