I see that many INFPs are somewhat moody folk, who struggle with issues of self-esteem.
Medicine? Start exercising. Simple as that. Now, that may sound a banal choice, but there is a reason why all psychologists recommend it. Endorphines that lash out during and after of exercise make you feel good and you feel better about yourself since you are respecting the temple of your mind, soul or whatever is this thing that is our subjective existence. Rock-hard abs, or that perfect butt you always wanted - have a goal, and work for it.
Muhammed Ali was once asked, how many sit-ups he does in one session. He said he doesn't count, and after it starts hurting too much, he starts to count. That's hardcore.
I see sports are no area of big interest many of us - it's not even for me. But nevertheless, it makes it more important for us than many other things.
One guy in Youtube commented about this video, that he had a suicidal friend. He showed this to him, and this friend of him got his shit back together, started to take responsibility and started having goals in his life. That's just damn cool.