Brutally honest yes, because we want you to see what is going on here. Look, we could lie to you and you could make the same mistakes over and over, and to be honest with you that's what my friends always did to me, because they never wanted to hurt my feelings. Well, I'd rather my feelings be hurt now if it meant a better future and understanding and that is what I think we are trying to drill into your head.
Nothing wrong with that, it was hers to. But you have to understand the dynamics of a relationship, which you don't, and that is what we are trying to explain to you.
You may not know how to be the best boyfriend, but come on, the stuff with the other girls is not rocket science. That being said you are at least honest about, which to me still counts for something.
Then you have to do exactly what your mind tells you shouldn't. You have to pull away from her and focus on your own life. Because the only relationship you will ever have that will last is the one with yourself. Right now you are so focused on her, that you have made yourself secondary which in turn has allowed her this power over you, which in turn is driving you nuts, which in turn is depressing you even more. It's a never ending cycle.
What she did was get off the downward path and distanced herself from you, and now I'm suggesting you give yourself permission to get off the downward spiral for your own good... not hers (in this circumstance it is OK to be selfish) and distance yourself from her. Only then will you be able to put some focus into your life and move forward with a clear head.
This is what I mean. I think you shouldn't worry about her right now. It is easier said then done, but worrying about her next move does your mental and emotional state no good. Your next move should be about your own next move, which is not bullying her, but bringing yourself back up. Be honest with yourself, if you were her, would you date you? Of course not, your not in a place where you can think straight, and she knows it. So back off for now and see where it takes you, with you.