How old are you?
If the weather's nice, go for a run. You'd be amazed how some fresh air will help.
If you have a cuddley pet, play with it, cuddle it, cry with it.
If you have a job, work your ass off. Sooner or later other coworkers are going to talk to you and even though you may not share the same interests, you can at least bitch about work with them.
If you have way too much free time, just post random stuffs on the forum :p Someone's bound to want to talk about what you just said eventually.
Blast your favorite music and dance 'till you can't dance.
If you're too tired, grab a couple of pillows. Cuddle that, cry yourself to sleep. Just don't do it too much as it might make you lazy like it did me.
I've lost my friends and had to start over from scratch twice. The first was my freshman year in high school. Apparently I was too 'weird' and not cool enough for my group of friends so I was ostracized and I had trouble making new ones. The loneliness and depression was so great that all I wanted to do when I came home was just sleep so that I could forget it all. I thought about suicide on too many occasions, but I never tried it. (I guess a part of me thought I'd be okay some time in the future...) I did it so much that my grades dropped dramatically and I became so lazy that I still have more of it than I'd like today. To this day, I don't remember how I met my friends or how I made them, but with time, it happened.
My senior year, I had trouble with my 'best friend' and found out that we had feelings for each other, only at different times, while we had conflicting interests with others and she slept with a guy. Basically that blew up in our faces and my clique chose her over me because apparently the only reason we were friends was because I was friends with her. Go figure? I was heartbroken and betrayed, but by then I discovered more about who I am and knew a lot more about myself thanks to the MBTI, although I don't suggest you invest too much time relating yourself with INFP too much or else you force yourself into a corner and you act accordingly to how you THINK an INFP should act else you become a self-fulfilling prophecy. Think of it more as a tool that will help you discover MORE about yourself other than your COMPLETE self.
Anyway, due to great timing and some sort of divine interference, I started my job the exact time of the breakup. I worked my ass off + overtime. Eventually I got to know my coworkers and they've actually become my best friends, even though we don't share a lot of the same interests. I'm at community college right now and I've yet to make a single friend. I was kind of depressed about it for a while, but I got over that thanks to my cat and coworkers. I have no idea how I'm going to cope once I move out to a four year college, but right now I'm content with my somewhat loneliness.
I can count the number of friends that I kept my entire school life with my left hand, and only half of them I still talk to on a regular basis, and only one of them I still feel close with.. to an extent.
Take your time to recover. When you feel a bit better try to communicate with people more in some way. Forums are great for introverts because it doesn't take as much energy to expend as it does in real life. Get to know yourself better. The more you know about yourself, the more comfortable you are. The more comfortable you are the more confidence you have to talk or decide to not to talk to people.
If you're a creationist, that's just how god made you.
If you believe in evolution then nature randomly made you to test what you're made of. INFP's aren't extinct so we must be doing something right
There's nothing wrong with you being who you are. Unless you're like a rapist or murderer or something.. THEN you're fucked.