Why do old songs make me sad?

[wakeel55]

So ever since i was 15 i noticed this weird thing about me. How come I feel some sadness when I listen to old songs? Also, some weird shit happened to me few months ago, i was off tramadol(painkiller) so i was having withdrawals but i fell asleep coz of weed. But then i had a fucked up dream of me beating up my dad coz all he does is takeaway all my happiness coz in my dream he kicked out my uncle whom i really loved. THEN, I fucking woke up coz of my lil bros alarm and when I woke up i was ALREADY crying, I dont even remember the initial tears, i was already in the middle of crying right when I woke up. (Dancing in the moonlight song was playing, it was my little brother's alarm) 

[frnsh]

It's really OK to feel sad, cry and express your feelings. Which parts and how much they bother you? Do you think you may be depressed or does it mostly come from being open to your emotions?