What do you suggest if i am 17 yrs old year old guy.2 days ago i noticed weak erections and now i can't even maintain it?

Don't stress: While erectile dysfunction predates heart disease in older men by 10yrs, in younger guys like yourself (17yo vs stated 33yo), it's most likely a stress issue. Think of it as performance anxiety. Perhaps you just broke up? Or are feeling guilty due to cultural or religious reasons? Tobacco never helps erections regardless of age. Excess alcohol too (altho any is considered excess at your age).