Mental health unstable. Assistance!

From last 3-4 yes I am experiencing change in my lifestyle i was healthy and happy with my living now I am seeing myself in sort of sad & dull in my life concentration and focus is not at all in my life I don't like going out not able to socialize not able to enjoy any activites which I like earlier unable to maintain or memorize even minor things due to which I lost many things in my life and time due to which I am always late reaching places. Due to this condition even I have gained weight and also my eating habits has gone worse and also because of weight issue I am unable to sleep peacefully.if I sleep for 3-4 hrs I get dark or bad dreams which is like nightmare or sometimes I couldn't sleep due to overthinking about my future as this impacted my whole life and i was not able to achieve anything .i am tensed due to these situations as I got married recently and unable to understand the gravity of this condition am I am depressed or is it my assumption. do i need medical assistance