Hi There!
It could just be it is time for your hair to shed. Everyone goes through this natural phase.
When this happens to me (and I panic 'cause I have such thin hair already!) I deep condish with ORS Replenishing Pak or use a light protein conditioner which will slow it down, but not stop it all together. Then, just as soon as the shedding started, it stops.
If you have breakage then a heavy-duty protein treatment like Aphogee or Emergencee might do the trick.
HTH!