Mending a failed relationship that lasted for less than six months is difficult than failed relationships that lasted more than six months, especially from one year-onwards.
The only option you're left with is to ask for forgiveness.
Her response will determine the status of the breakup. She will accept you back or say she doesn't want anything to do with you.
Be humble, use polite language, and explain why you reacted in such a manner. Let her know you are sorry for how you treated her, and that you love her, and hope she'll give you another chance.
It's better you call her. If she doesn't pick up your call or picks it up but the conversation doesn't turn out as you expected, send her a text.
Don't pressure her if she refuses in both instances. Don't force. Let her be, that is, give her time. In a couple of days, a week is better, contact her.