Seriously what's wrong with my body

For the past two months, whenever I lay down, I feel my heart beating beats slowly suddenly , as if its gonna stop or something like "like mini scared thing but it's slowed and hurt" and can't breath during it, gotta quickly sit down and boom back to normal.

It's start differently at first like , whenever i hear a bad news or something that bothers me , it was hurting emotionally at first "like normal ppl feel" but it's start hurting me physically , I feel my heart doing the "screenshot" pain ... and it keep beating fast till I feel calm (it takes me half hour to get back 2 normal) but as I said I think this thing develops and did something 2 my heart... 《side note: I'm stressed person,  anxious , over thinking that effect my sleeping , I don't get enough sleep ... its like 3 to 4 hours sleep a day ....damn I'm a mess》