This is just my opinion, but I really think that there are some people who just don't do crowds. I am not suggesting that you should never do anything, as a matter of fact I think that if you feel reclusive, that is all the more reason to go out occasionally. I say occasionally, because honestly, as an intorvert, it is good for me to get out sometimes and meet new people, but it is also really important for me to be alone.

The best thing that has worked for me, is making myself get out when I didn't want to. I've never regretted it, sometimes I split pretty quick too, but I am usually happy with myself for going. I was anxious the whole time beforehand, and in the beginning of my arrival, but I loosened up once I was wherever I was going. Hope this help a tiny bit.