Why does my macbook pro 2018 13inch with touch bar is having an issue regarding battery life and heat problems.

Hi there my name is Jefry, i have a question regarding about my concern to this laptop. So basically i bought the laptop in february or april 2019 i forgot. I have used it for my school stuff such as editing programming, etc. All seems normal battery can stay like a day and no heat problems well there is still but its not overheating. Suddenly like 3-4 days ago, my laptop suddenly face a problem regarding its battery life and heat/thermal problem. My laptop is used normally but i can tell a big difference. The battery is getting shorter and the lifetime too. Also i open my laptop for only like 20 - 30 minutes and it has heat problems while actually i used in a room with 18 degrees celcius on. Pls someone that ever had this problem reply to this post.

BTW

maybe my laptop issue has a relation to what i've done. I dont know either but one night i charge my laptop. I wait in my bed while playing my phone and suddenly i fell asleep. Then i woke up in the next morning like 4 AM in the morning and i was shocked right i forgot to unplug the cable from my laptop. Maybe this is the cause of why my laptop battery drain so much and there is heat problems too? Pls i need answers. I might put my laptop in apple service center near my house. But i need to see if someone will actually reply to this post cuz i really need to solve this quick.