Talk to Sexologist on Sexology / Nightfall

Assalam O Alikum.

I am facing nightfall / Ahtalam problem every week sometime 2 or 3 time in a week. This problem is continue from last 3 years and i married 6 months before but after marriage the problem is same. so i want to know is this a serious issue or it is a normal case. If its a diseases so what is treatment for it? And also every time i feel tired in normal situations and working hours. I am looking for your kind response.