You realize what she's doing, right?
She's wanting to go explore other options, but she doesn't want to lost YOU as an option either. You're her fallback plan in case the other options she's exploring doesn't work out. That's usually what it means when a girl calls you, but is a bit skittish about hanging out or going beyond a certain point. Not always, but usually (for those who will come in and say that that is a generalization, well, yes, of course it is
and I know there are ladies here who don't do that
).
So the first question you need to answer for yourself is whether or not you are ok with being her "fallback plan." (I would assert than no self-respecting male would be ok with that, but that's just my opinion)
Second question, then, after you answer that one is to ask yourself what has changed since you split up. I'm going to go out on a limb here and say very little has changed. People don't change overnight (that is, YOU didn't change chief, not her
). So the problem is still going to be there waiting for you if you get back together.
Granted, I wouldn't be comfortable with a girl who maintains contact (or resumes it) with an ex either, so I think you were fine to be a little wary about it. But I'm betting you didn't handle it right. Figure out where you went wrong (you sound like you are too accomadating, clingy, and haven't set any boundaries in your relationship, so, instead, you try to manipulate the relationship--and her--so that you don't have to set those boundaries), and fix it.
But I've seen this type of situation a million times. 9 times out of 10, the person who is in this situation ignores all the advice that is given to them, runs back to the gf without doing any of what I suggested above, get's together for a while until she dumps him for another guy a few months down the line.
Ah well, I'd worry more about why you are clingy than whether you should get back together or not. Take some time to focus on yourself and don't lose that focus in the relationship when you decide to get back with her.