Okay, this can be for a lot of reasons. If you have long hair and you comb it out, it will seem like a lot more because of the length. It would be a good idea to separate and count them.
There is a natural fallout that our bodies normally do. If your hair doesn't look thin, then you should be fine. Another thing to look at is the family members on your mother's side. You will want to see how much hair that they have. Genetics can be a large factor as well.
If you have lost a large amount of weight, change in your health, or surgery, it can also affect your hair. Surgery can reek havok on your hair. If you have had one in the last year, that could affect any of the chemical services that you have had. You also could be on some medications that will create averse affects to chemical services as well. If you have had a chemical service or two that has compromised the integrity of your hair, you could be experiencing a great deal of breakage and fallout.
If you are seeing some small hairs that are growing in that is a good sign, unless there are a lot of them. I would say that it is from chemical services that have burnt your hair off. If you are getting chemical relaxers done on your hair, you need to be careful to not overlap the product on hair previously relaxed because the integrity of the hair is dissolved and within a few days after the service, your hair will be coming out. You will need to get your hair cut more often to keep your hair from looking too thin on the ends.
If you have gotten a perm and the rods were too tight, the bands of the rods bent the hair, if the waving lotion wasn't properly rinsed out, if the neutralizer was kept in the hair too long, and/or the rods in the hair were pulled too hard it could have caused breakage as well.
I would go to a good hairdresser and ask if they can figure out what is going on. If that isn't determined, I would talk to a doctor to see if it is a symptom of another problem.