Should i seek help for my depression?

I'm 17 and pretty much ever since i can remember I've felt depressed most of the time. Well apart from when i met my now ex boyfriend, he made me happy until he cheated on me and then i just felt 10 times worse than before but regardless i still stayed with him but tried countless times to let him go until eventually i ended up cheating too, which disgusts me. So were not together anymore and for the first few weeks of no longer being with him i felt happy, or perhaps numb but either way i had stopped crying almost every night like i was doing when i was with him. Until we caught up about a week ago and i found out he was seeing somebody else now i just feel shit again, which i know is normal after ending a long relationship, but my constant depressed feelings are effecting my relationship with my group of friends too because it seems as if no one wants to be around me because i am always down (this has been ongoing), i know these aren't my true friends though but there still good to have around to go out with on the weekends. I do have my best friend who has stuck by me no matter what and i have an amazing family so i feel pathetic and ungrateful that i am still depressed but I'm just getting sick of feeling this way. I start my further study at tafe in Feb and i am afraid my depressed attitude is going to make it difficult for me to develop new friendships, and i am also just so sick of this. My mother suffers from depressions and is on anti-depressants so should i seek help or just keep on trying to wait it out? please help <3