Sorry to hear that, dude. There are a couple things I wonder. First of all, how are you as a drummer? Are you really steady, tempo-wise? Can you get through whole sets of music without any major mistakes? Are you careful about not over-playing? Praise bands have a job, and the #1 priority in that job is to not be a distraction.
Also, had they tried to talk to you about stuff to improve on? One big problem I've seen in churches is that leaders don't want to come across as harsh, so they make "subtle suggestions." They want to say, "Ok, dude, your tempo was all over the place, and the 2800 fills you played in a 2 minute ballad just didn't work," but instead they say, "Hey! Great job. Really nice work. I can see you have some awesome chops. Maybe just try to be a little more controlled, but overall, that was fantastic." This is not the right way to handle it, of course, but it happens, until they are so frustrated, asking the other praise team members, "Why doesn't he get it?" when you are telling people at home, "The worship leader gave me 100 compliments tonight!"
The best thing you can do is sit down with the person who made the decision, and ask them why. It might be ridiculous. The only time I was almost ever fired from a worship team was when I was playing harmonica for one. They decided that I moved around too much (I tend to dance...kind of sway...not like flat out dance, when I play). There was a whole meeting with the church counsel to decide whether or not they wanted me to keep playing, that I was not informed of. They agreed that I should, but when I found out about all that, I just quit. Another time, at the same church, I was drumming, and afterwards was being goofy with some friends in the car next to me, making faces and stuff (nothing obscene). The person behind us decided that I was trying to fight with them, doing the road-rage thing, and thus called the church and complained. I had to explain it, and the people in the other car were questioned, before I was allowed back on stage.
On the other hand, it might be a real reason. You might have things that you need to work on and don't even realize it. So, sit down with the guy, find out why he fired you, and then, if they are valid musical reasons, work on them. If they are stupid stuff like I listed above, then laugh about it, and join a praise band that isn't so focused on stupid crap.