Trimmer malfunction

Question

Up until a few weeks ago my shaver and trimmer worked well. But now if I use the trimmer, rather than trimming my hair, the blades put at it and try to rip them out rather than cut them. i can't say I've noticed but the trimmer doesn't seem to be moving fast enough to cut the hair. I'm not sure whether that is the problem or whether it's that or if the blades aren't sharp enough or what is goin on.All I know if that it is pretty sore if I try to trim my beard!Can you offer any help?CheersDan