I Am Here Because Ive Been Told I Need Help

I am here because ive been told I need help and I do feel as if going to a doctor would be helpful but I also then feel like I am fine most of the time so they may just think I'm a hypochondriac. I used to be extremely active, the gym was my favorite place to be. I used to love going out and doing things with friends, being around groups of people and meeting new people, but about a year ago that all changed for me. I had extreme insecurity issues to the point where I would starve myself, make myself throw up. I would even blend ice to eat as a snack so I wouldn't be getting any calories, and chew up food for the taste and spit it out in a bag so I didn't actually have to eat it. After a few months of that, I found my mood on things to change. I am an 18 year old female, 5'7 126 lbs, not overweight in any means, but I am not happy with my weight still. But instead of starving myself, I just find myself to feel guilty, and it adds on to the reasons I sometimes feel as if I just don't have a will to continue anymore. Last night I had another episode of feeling hopeless (they happen about once a week if not more). I was with my boyfriend and I went into his bathroom while he was sleeping and locked the door and turned on the bath considering drowning myself. Whenever these "episodes" if that's what they are called happen, I always cry uncontrollably for literally hours. I cant stop it and I cant help the things that go through my mind. Sometimes during the day I think about all the most painless ways I could do it if I wanted to. The thing that's so weird about it is I have no true reason to be so upset. Like I can be sitting there one second happy as can be, and the next I'm just so angry and upset and its hurting my relationship with my friends and my family. I don't know what to do anymore, and I just want to know if this is something I am going through because my mind is actually not 100% right, and I could actually get help, or if trying to get help is pointless because I don't want to feel this way anymore.