I may regret bringing this up, because with this type of thing I often end up being wrong, but I guess if I'm wrong that's another reason to say it, so at least it will be clarified. I've been thinking the following about you for a long time, but haven't mentioned much because, like the "getting over procrastination" thing, even if it is true, you aren't going to believe it until you figure it out for yourself as you don't have the proper experience. I'm finally going to bring it up though because it's been bugging me every time I hear you make a post about any sort of relationship thing.
By 'proper experience' I mean you haven't been in a committed, long-term relationship before. I may be wrong, but if I remember correctly and if this is the same ex I'm thinking of, you were only with her for a few weeks. If it's someone else, or I'm remembering the time-span incorrectly, then I'm just going to look like an idiot here. But if it was really only a couple weeks, then there's no way you could have loved one another. I'm not going to talk much about love because that's a word that's hard to define. But I think you've really experienced something closer to infatuation every time you think you've loved someone romantically.
Ignoring definitions, the point I'm trying to make is that you may disappoint each other, and unless you're prepared for that it's going to be really harsh if it happens. Even assuming she isn't with anybody, and misses you as much as you miss her, and wants desperately to be with you again, unless you're extremely lucky, it probably won't work out. You couldn't possibly have gotten to know each other enough to decide you're compatible for life yet. Even if you were somehow great at communicating and learned a lot about one another, you couldn't have gotten accustomed to one another's habits and moods that quickly. You may have known her well during those few weeks, but people change gradually. To get an accurate picture of what a person is really like, you kinda need to be with them for months or even years until you can tell who they actually are despite their circumstances. Plus, you've been apart for so long you both may have changed. She may not be the same person you remember anymore, even if you were truly perfect for one another back then.
Instead, you both liked what you saw, and learned enough about one another to build a representation of the person in your mind you were infatuated with. Only, because you couldn't have had time to learn that much about her, there were a lot of blank spaces you had to unconsciously fill in. And when you're infatuated with someone, you're extremely generous with those blank spaces. You tend to assume the best about the person until you're shown otherwise. And, on top of that, because it's been so long since you were together, you've had a lot of time to dwell on her and your relationship. The memory of how great it all was has probably be warped with time, and you hold her up as this one girl who was perfect but you let slip away or something. And your years of not finding anyone else has probably further convinced you that she was perfect for you.
One thing that makes me sure you couldn't have had much of a relationship, besides everything I've mentioned, is the fact that you just drifted apart and stopped hanging out without a planned break up. That type of thing just doesn't happen between people who are actually in love or have an even somewhat serious relationship. Of course I think it's a good idea to go out with her if you got along well before because there could be something there.