Most Helpful Guys
Heartbreak leaves a scar. Too many heartbreaks and you can be permanently injured and those wounds never heal.
How long has it been since your last break up? My guess is it has not been more than a few months at max.
What you're feeling is the natural defence mechanism of your brain. Your emotions have been hurt too many times. So your brain has built up walls around you which would prevent you from trusting people, falling in love or getting too close to anyone at all. I'm glad you have those walls up already. Most people bleed helplessly after such experiences because they still don't have those walls up.
This is natural. And this is necessary.
But this is not permanent.
As human beings our natural tendency is to be drawn to other humans. The walls will protect you as long as it takes for your emotions to heal. Then they'll disintegrate on their own. There will come a time when you'll feel as healthy, as unburdened and as susceptible to falling in love as you felt before you met your first boyfriend.
I don't know how long it will take for your walls to disappear. Healing period varies from person to person, and from situation to situation. But I do know that at some point of time they will. It can even take more than a year. But for your own sake, you have to wait till then. Whatever you do, do not force yourself into a rebound/arranged marriage or any such forced relationship now. Do not force yourself to be vulnerable again - your system has built those walls 'cause you're still not ready for the consequences.
Here are some practical tips to help you out:
How to Move on From Someone You Loved: 7 Rules
Q&A: How to Get Over a Devastating Break-Up?
Being Single: The 7 Principles of Enjoying Your Singlehood
How I Coped with Being Dumped and Why That’s NOT Going To Help You
All the best. :)