Help, I think my baitcaster is sick!

[Twinsprtsfan]

Well, I went fishing the other day and was doing great, caught 12 LM Bass, and a couple of those were 4 LBers. But about halfway through, I noticed that my baitcaster, after I reeled it in, was not working right. Here is the problem:

After I reeled it in, it would not stay "locked" and the bait would just fall or get swung into the brush or grass. In other words, after you cast it and turn the crank and lock it to start fishing, it is not supposed to slip. But it was. Not after every cast, but enough to annoy me.

After I reeled it in, I could reel it a little forward, and go the otherway backwards and it would slip some. Now I am fairly new to fishing and especially baitcasters, so any advice I would really appreciate. It is a Diawa Samurai left handed (I know, that is my first problem) baitcaster. I love the rod and reel, just wondering if I am going to have to go out and buy a new reel soon. Thanks.