Just Feeling Really Sad All The Time?

Hello yahoo, I don't really know what to do. I just kind of hate the life I'm living. I do understand things could be so much worse but I'm just feeling really sad. I feel lonely, and like I'm not really worth much of anything. I can't even get along with my own mom, and I've started to really hate the person she is. She told me all this stuff about my dad that I used to believe, and I used to view him as a bad guy which he really isn't. I cannot bring myself to blame him for leaving the house. She has taught me to believe he left us and so on. He didn't, he only lives 15 minutes away and has always maintained constant contact with us. She just has some habits that really make her unlivable with. She makes me feel like **** all the time, nothing I ever do is right. I enlisted in the USMC, I leave July 18th, and yet that's not good enough. I could do so much better, and I have problems for wanting to do it so on. I think of it as an honorable position and my dad has been supporting me all the way which I really need. My mom used to always tell me if it's so bad here go move with you dad, so this ped summer I was so tired of it I said I'm moving with my dad, and when she saw I was serious, she started pulling the guilt thing on me started crying and talking about all she had done for me and so on... What did I do? I stayed... like an idiot. She's been doing some super dirty **** to me these ped few years to me too. I'm a minimum day student, and yesterday, I called from school after my cles to ask if she was going to be there to pick me up, she said no, she couldn't make it in time to the school so I'll just have to catch the bus (an hour and a half later). Luckily one of my friends from the neighborhood was leaving early that day and he gave me a ride home. I walk to the door and it opens up, there is my mom, in frickin pajamas. That **** kind of urked me a little bit. But this isn't it, she's a pathological liar. She's been unemployed for over a year now (she doesn't know I know, I found out from her boyfriend). If she would just tell me these things, things would definitely be easier on all of us. This is the week of final exams for me, I leave school Thursday and Friday early (10:02). I informed her of this last Friday, and asked if I could use the car on these two days, she said yes. Well yesterday I asked if she would be able to pick me up from school today on time, she said 'yes, but i don't know about Wednesday and Thursday' so I'm like hold up, you said I could drive on Thursday. She's like 'well i'm not concerned about that, I got to be at work to keep this family under a roof'. In my head I'm just like you bullshitter you don't even have a damn job, and you keep this family under a roof by mooching off your boyfriend. She's always made empty promises to me. I'd rather you just say no then say yes and not mean it. She promised me a car if I got all A's last semester. Well she must not of thought I could do it, but I tell you what, i really wanted that car lol, my lowest grade was a 90. Car? Nope. It wasn't a big deal because I doubted it would happen from the start but she just acts so serious and is like 'I'm dead serious and I mean it' but I'm always just like sure mom... But I don't know I just feel miserable living with her. I gave her every cent I made over the summer to put to car insurance, well you can count the amount of times I've driven with your hand. I'm regretting ever doing that. I've been lacking much of an appetite, I always leave for school in a bad mood, if it wasn't for this 1 girl in my second block, I would've already probably killed myself. She's always there for me and a listening ear thank God. Please don't misunderstand me, It's not that I'm complaining for not having my way, it's that one should do as they say. If I cannot do something for you, I will not tell you I can, and mislead you into believing that I can. I will frankly say, no. Which is fair.