Getting nervous for no reason. Tell me?.

Hey guys! So I felt a kind of nervousness around my chest middle portion, around 11 pm in the night and then by morning I was still feeling nervousness. The nervousness was there and I was feeling slight heaviness in my chest, even in stomack and also kinda in my left hand (that made me rethink more about it). Now it's August and till now I have experienced this 3 times, I feel sudden nervousness that then leads to feel heaviness and overthinking. Today I was havin gol gappas in the night and I felt a lil smthn in my left side of chest so little bit so u started walking and felt okay. Before this even I felt slight chest pain in right as well. I overthink a lot and last time I was struggling kinda to breathe even. What it could be? Also whoever I eat anything junk I go straight to the washroom, even now I am Goin to the washroom like more time than I usually do. What's it? Please tell me?. And I am 21 years old and I feel what it could be.