Young and feeling something strange

I literally just made this account cause I just cant shake this feeling. I'm gonna describe myself and see if someone can relate and throw some advice my way so i can get my head back on straight.

Im 19, male and been threw some stuff (not a sob story). No mom, dad or siblings anymore so its just me. Im confident and most people like me right off the bat. Im playful and always smiling. Not a pretty boy but im pretty easy othe eyes apparently.

Cut to the chase- Yesterday morning I woke up and had a deep sinking like sadness in my chest, usually id say screw it and forget about it but it just hangs arounds and at work today it felt unbarable (like i couldnt focus on anything). Started thinking about my life and past too see if i could think of something to trigger the feeling but no luck. Loneliness? Depression?