13 year old has many body problems. Help.

hey im my name is jared im a 13 year old male and ive been having problems with my body i will tell you all my syptoms. it all started about a month and a half ago with a head ache and sore eyes and picked up from there with a cold and got bad, ive been having problems breathing short of breath, and ive been having problems getting a full erection, i get the odd hard one here and there but sometimes its really soft, it is not normal for this to be happing, im pretty healthy in my oppinon my mom says i am and everything, im 140 pounds and 5 foot 8, when ever i run alot i have pains in my chest and have thick saliva and seem to cough sometimes after that, i did smoke for about 2 months which i tottaly regret and stoped as soon as i can, i take a vitamen C or 2 every morning for the past 6 months to a year and if not everyday every other day, ive been trying to eat way healthy then i was before because i never ate as healthy as i should have, i have been kind of stressed because i have a low mark in 1 class and its my first year of high school, along with my mom loosing her job which she has been with for the past 30 years, i didnt play basketball this year since i wanted to see what my grades where at for the first year of highschool i am pretty active but not latly. i have went to the doctor when it first started and havent gone since because i didnt want to pay the money because our health insurance ran out because of my mom loosing her job. could it be stress? diabetes? <---- (dosent run in the family that i know of) a cold that is sticking around in my body? lac of activity and body is lazy and acting up? puberty that is causeing this? hormon inbalance? body growing?. please help me i dont want to be like this any longer. could it be anxity? my breathing has gotten better but is still here. im really worried about the erection problems. and most worried its diabetes. HELP ME PLEASE!!!!