First of all, yes, your boyfriend will hit you again. If he’s hit you once, and you continue to hit him, chances are he will hit you again. So, I hope that answers your question regarding his hitting you.
That said, if you are a violent person, which it sounds like you are, you need to take this problem seriously — more so than you have. It’s the only way you can cure yourself. You need to stop dating this guy today. In fact, stop dating everyone. Hitting — even slapping — is a crime, and you could easily find yourself in jail. And that’s just you — you are hurting people around you by hitting them — and by their seeing you get hit and hit people, and knowing you’re involved in violence.
I’m not surprised you’re depressed or lonely and violent, as well. They often go hand in hand. Violence is usually a last resort when you feel you don’t have other tools to make yourself feel better — and that’s exactly what you have to work on.
So, after you break up with your boyfriend and stop seeing him, I advise you to simplify your life. Work, health and exercise, family, friends — and that’s it. Making it simple will eliminate the chances of your getting overwhelmed and lashing out. Once you simplify your life, I want you to focus on your own health. I know this sounds silly, but being healthy physically is directly correlated to being healthy mentally. Start eating only healthy foods. Exercise regularly. Join a gym. Focus on doing well at work. As you add in a social circle, eliminate ANYONE AND EVERYONE who is violent, abusive or hurtful to you. Only spend time with people who are healthy and supportive of your health.
When you do that for six months, you can then start looking to date again — but this time around, zero tolerance for violence of any kind from any one.