Yes, understandably you sound depressed by the situation. Do see your doctor.
Here are my tips for getting through a similar situation:
Build yourself up. You absolutely need to do this, teenage hostility is highly wearing and erodes your self-esteem. Get out, do things you like, do not feel guilty about this., You need to believe in yourself and be strong to be able to help her. Do you have friends/ work colleagues to confide in? DO NOT feel ashamed, you haven't done anything to deserve this, you are not a terrible mother and honestly you will find many people have been in the same boat and are lovely and supportive.
She is using you as a battering ram most likely because she feels bad about herself. It helps to find a balance between being kind and not taking nonsense. Ask her how her day was, tell her goodnight, buy her some little thing and say I thought you might like this. Try not to disengage from being a normal parent even though it will feel like acting and might be through gritted teeth and may not seem to get much in response. When she comes out of this she will need to be able to remember that you were always there for her.
But do disengage from the abuse - practise a few phrases to use for when she's kicking off -"That's not kind". "That's rude", "That's not true". Use these instead of saying you e.g. avoid labelling speech like "You're really hurting my feelings". Do your absolute best not to let her see you upset. Learn to walk away. Make an excuse if you have to and 'go to the shops' for some urgent thing. Sit in a car park and cry and scream for a while!
It will get better. Even if she walks out, and I hope it doesn't come to that, if you can keep strong and love her and let the worst blow over you without knocking you down, you will be able to reconnect later on. Think of her like a toddler having a tantrum - as the parent, you would deal with it and help them through it even though it's stressful and annoying and invariably at the worst time and embarassing in public!
I did once have to call the police for abusive behaviour. It was absolutely awful - I was at rock bottom at that point and it will always be a tricky thing between us -but she has never behaved like that since. So I think I did her a favour in that respect, even though she doesn't see it like that yet.