At what age did the women in your family start their periods ? (find out about her father's family, too) I suspect her hormones are beginning to kick. It causes stress. As her internal stuff begins to change and cycle, her body is coping with it, but when things go wrong, she just doesn't have the strength to cope with them. Think about what it's like to "pms", and you'll see the reflection of what's going on in her life. Generally, age 12 is a kind of hell to live thru, but it sounds like your daughter turned 12 a little earlier than most. The good news? The next year is coming. Expect that in about a year, this stage will change and things will get better. Also, around age 10, be sure to be sure she's aware of the monthly cycling that starts somewhere in the early teens or sooner, and have some supplies on hand for her when she starts.
That said, I suspect you need to be listening to her even when she's a bit hysterical. Find out what else is going on in her life. When she cries, I wouldn't walk away if the other option is to hold her and let her know you love her. It's especially hard when you're tired from work and she's exploding, but I think the drama will calm down if she feels heard and understood. Ask questions, listen, repeat her last few words as a question, and keep her talking. The more you know of what other pressures (social, most likely) are imploding on her, you'll understand why she's exploding on you. (The easiest method of "active listening" is to ask a Q, for example, "How was school?" She says, "Not so hot." You say, "Not so hot?" and wait -- with eye contact. Hopefully, she'll respond by adding more to the conversation. "Everyone laughed at me today." "They laughed at you?" It sounds very canned, but it's worth trying. Try to "peel the onion", listen to the peripheral stuff, and as you work thru each of those items, you'll get down to the stuff on the inside that matters most and is upsetting her the most.
If she feels everyone hates her, then you need to really listen to her, not walk outside and hide from her. "What makes you think that?" "How do you know they hate you?" "How would they act differently if they liked you?" See if you can get under this. Self esteem is a tough nut to crack, but you want to do it. She needs your support, and if she's saying that, she's sending you a message. Don't wait until it gets more serious to be listening.
And most of all, take a deep breath. It's quite probably a stage. It's not forever. It's okay to get to a point where you don't feel as if you "like your child." But hang in there, do what you need to do to really listen, to show her you love her and to sleuth out whether there are any serious issues going on her in life (serious to her) If it is a stage, it WILL change, and she'll return to the child you have raised. But it does take time and growth for her to live through this part of her life.
That said, do pay attention to the social/physical stuff going on. . . how is she eating? Sleeping? Without enough iron in our system, we are generally exhausted, and exhaustion reduces any reserves we have to deal with stress.
Good luck, Mom. It makes the end of the day, when you're tired, tougher, but hang in with her. The more you listen, the more she shares, and the more she shares with you now, the more she'll share with you later in her teens, when you REALLY WANT her to be listening to you and sharing with you to hlep her to cope with and navigate thru her teen years.