why am i sick 15 days to three weeks out of every month?

[Emily882468]

So for a little back round info I have been very prone to allergies since I was very young like 3 years old but when I got into sixth grade I started to develop chronic bronchitis with this I got sick once a month for a year and a half and I still have random cases but then it progressed in mid seventh grade to the point where I got sick like two weeks out of every month but that was not all now I'm in eighth grade and I am sick 15 days to three weeks out of every month usually this adds up to three times a month now I did have blood work done but it came back normal if anyone else has experienced this or knows what it is I would greatly appreciate a response.

Also  certain answers like get more exercise [ I am advanced gymnastics], You are stressed out I have had evaluations to test stress levels and they were all normal, hygiene is also not an issue because I always keep hand sanitizer on me and my house is always disinfected.    :]