Could i have postpartum depression? (new mom)?

I'm 19 and have a 5 month old and i'm married to a guy who i am not happy with but i'm stuck with him now cause of our son. and i think i might have postpartum depression. because at my age i am a stay at home mom and literally do nothing all day besides taking care of my son and watch tv. and taking care of him is overwhelming. i feel angry alot that this is my life, i should be out having fun and enjoying my teenage years instead of doing late night feedings. and i daydream alot about my past before i met my husband and i think about what i think my life would be like if i had never met my husband. i can barely even listen to my ipod anymore because almost every song makes me think of the days when i was really happy...and then it makes me miss those days. and makes me miss my friends. does it sound like i could be depressed? or am i just very overwhelmed?