Deek, my condolences re your lost relationship. My personal opinion after being through a few of these on both sides (old guy here, but I swear I remember being 27...felt exactly as you describe) is, this happens all the time to someone and you didn't do anything wrong; it's probably just her own quirk.
More detail:
1. I dated a wonderful woman who was 24 and then 25 (I was early 30s). She broke up with me after seven months. Later, I realized that she broke up with everyone the same way as she broke up with me.
2. Her breakup technique shouldn't be the issue. Strong disagreement with the fellow who called it psychopath. She communicated gently but clearly and indicated there was prep time. You may not enjoy the details, but they were fair and do indicate it's over. IMHO, very fair.
3. Again, this happens all the time. Most relationships end with someone dumping someone. Most of the others end by "cheating" - an affair in which the prospective dumper jumps in the sack with somebody else. Option 3 is the leaving party picks fights or otherwise mistreats the dumpee, hoping unconsciously to drive them away. Unless you AND her were ready to marry EACH OTHER in the VERY NEAR FUTURE, you got off easy compared to the other options!! (My apology for caps - just trying to emphasize how specific the conditions have to be to prevent some sort of breakup eventually anyway.)
4. It may seem now like options are few, but they exist, and you will find them. The sooner you move on, the sooner you'll find the right path forward.
5. Great respect for the intermittent remarks that you will move on. Do that!
6. You are experiencing a lot of pain. This is significant because it says about you that a personal relationship like this is a big event for you, but also one hedged about by barricades of pain. To the extent possible, I suggest:
a. Recognizing this as part of the sequence for you
b. Knowing it won't last forever
c. Journaling some of the pain details for clarity
d. Getting some emotional counseling if possible, to maximize the healing so that the pain is temporary and a growth experience rather than a pointless banging against a permanent wall that limits you
7. Do everything in your power to lighten your approach to these things, including every step of the moving-on process, the meeting-people process, the living-alone process, etc.
8. Definitely do whatever self-improvement ideas you have, unless they cost more than $1000 (replace my arbitrary number with something you feel is reasonable, but please no more than a month's pay). You'll feel better whether anyone else cares about the specifics.
9. Do take actions to add some new friend network or social activity. Take the actions, whether or not they have the effect that you want. Do them even if they "work" and you still feel bad.
a. Underlying goal A for this is to exercise your socializing so you remain/become/are proven more than ever to be a socially competent, decent guy.
b. Underlying goal B is that human contact helps everyone, even introverts, so take action to add it.
c. Underlying goal C is to be a proactive, respectable self sufficient Man Who Has a Life rather than a pathetic sad sack who is not just lonely, but at the mercy of the one woman who dodged his clingy bullet by dumping him. I don't think this latter view is at all accurate, but it's the kind of subliminal feeling that you might think yourself if you stay at home consistently. Get out of the house, even for little things; you'll win the undying respect of both your future dates and your own subconscious.
10. Once you've done 9 - as soon as you like, or feel capable, whenever is first, do try some more dating. Do it as lightly as possible, but my point is, don't plan to finish your self-improvement program before dating, just do each thing as soon as you're ready/able. My deepest point on this is: The breakup was about her, not you; you're probably fine already, probably exactly what your future wife is already looking for. She's probably looking right now - don't make her wait too long. :)
Best wishes!
PS. If you're going to follow or re-read any of our suggestions, I suggest
@Villanelle's. She a wise poster. Plus, being an intelligent woman near your likely target age, her advice is a particularly good guide to what similar women (aka future date/mate possibilities) are likely to think. Her answers are a good sign for you, I bet.
Ok, I'm off to a track meet...my own cheap date... :)