Having a hard time breathing?

i'm so worried about my health so much that its sickening.. and i'm only 18.. but for the past 4 weeks or so i have been having trouble breathing. i do have real bad anxiety so my doctors and i have been asuming thats whats causing it, but i still worry about it. i was at the doctors yesterday, my pulse was 60, blood pressure was 120/72, tempurature was 98.8 degrees, and she tested oxygen level in my lungs and it was 100%. also a few days ago i was diagnosed with herpangina. but all tests show i'm healthy. i suppose the only reason i still worry is because i get chest pains here and there, and i have lost my appetite lately. i haven't had the desire to go out and do things i found fun before. i use to be very physically active and the past 2 weeks i haven't been.. i don't know if thats because of herpangina or something else. your input would be greatly appreciated