It freaked me out when so many people I don't know stopped to talk to me.
What do you mean? Why did that freak you out?
I just get overwhelmed by unknown people talking to me.
I know it may seem odd when people you don't know are coming up to you in numbers talking to you. It's expected that new people would want to introduce themselves to you, you should take this as a compliment not be off put by. If you continue to be off put by it, it may block you from making new friendships.
Hmm, maybe I need some help with that.
If you're having trouble talking to new people, then it might be good to get some tips on how to get better at it. I'm sure there are lots of resources available that can help you learn to be comfortable in conversations.