Premature Greying of Hairs at age of 17.

I saw 2,3 white hairs at the age of 17 and then it increased to like 10,12 now when I am 18. Some of them are always exposed and everyone can notice them sometimes. Sometimes they are hidden. It's not too much but my family can point them too often nowadays. My medical history:I have high blood pressure from the age of 15 and now I am taking BP meds: Concor COR 2.5 and Myotan CN 40/10. I also have high sugar but not diabetes,it's 100 in fasting. Also my cholesterol levels were high-normal,but doctors said they are ok.I also have L5-S1 disc herniation and degenerative disc disease in my spine.I took root block injection and many medicines for months like maxgallin 75,shine 10 mg for months,wysolone 40 and aceproxyvon for 5 days. Also have stomach/intestine problems(IBS,Grade 1 fatty liver,frequent stomach infections,diarrhea,cramps etc.) and a lot of stress everytime. Will all my hairs become white? Can I stop it? what about the already white hairs?Help doctors,I am worried at age 18.