Smooth stool but constipated. Need help.

I am 20 years old male . I went out from my home for study on July 2019 and Due to study pressure and lack of time i destroyed my eating habits.. I started living empty stomach for long.. I would go to college empty stomach and then Tuition.. i would eat some snacks like samosa in between and them come back to my room at 4pm and then i used to eat Rice... but i was not facing any problems.. All of sudden in November 2019 i started feeling constipated.. my stool wasn't hard but i felt like i am not done. I felt like stool is stucked in my rectum but doesn't come out. Time passed but i didn't get well it's been 3 or 4 months and i still have problem.. after stool i feel burning sensation in my rectum. There are sometimes mucus in my stool.. i usually don't have pain in stomach...it's just popping problem.. i don't feel fresh all the day...i sit in toilet for more than 30 min but still i don't feel clean in start it comes out in small quantity but after that nothing comes out I need help.