Are you skinny? lol
Some people just benefit A LOT from gaining 5lbs of weight.
We have that problem in our family. Everyone in our family is slim and tall. All sorts of odd health problems but nothing like......diabetes and joint problems.
A lot of people in our family get sick easily but anyone who is a bit thicker or normal size is super healthy.
My grandma @ 87 spent nearly 2 months in the hospital during a span of 1 year. She started eating more and hit 100lbs and she never got sick after that. She's 91 right now and she's doing things on her own lol
OR it could be insanely bad.
Doctors are so important sometimes
What we all can say for sure is your immune system is a bit weaker then the average person. Now you just have to figure out why