I'm 17, about 5'1" and weigh between 99-102 lbs. Is this a healthy weight? About a year ago i weighed about 110 and everyone told me i "looked healthier".

For the past couple months i've been sick between a stomach bug (which turned out to be an actual digestive problem and im still battling with it), then i got strep throat, now tonsillitis. So i lost those 10 pounds within a 2-3 month period.

I just lose weight so much easier than i gain it and my mom thinks im "trying to lose the weight" when i honestly eat everything and anything. Now i found out i might have to get my tonsils taken out in a few months and will probably lose another 10 pounds because of the restricted diet after that kind of surgery.

In summary:

-is 99-103 a healthy weight for a 5'1" 17 year old girl??

-any ideas on how to gain about 10 more pounds in 5 months for someone who doesn't gain easily??