How much hair loss is too much?

Im 27 f and have 2c hair, it was once really thick but over the years it has thinned out a bit to become mostly average. It used to be as thick as a silver dollar coin, but now just about a quarter. I wash my hair every 3 days to help with growth and natural oils, etc. Maybe it's because I wash it too little? I've gotten better about using clips instead of hair ties but it still looks about the same in loss. I've always been concerned about losing so much every 3 days but I just never had the guts to ask if it's a real issue? Please let me know! It's always been about this much as far as I can remember.