I told a guy I like some of my problems and he ended up giving me his number to "text him sometime", but now I feel embarrassed about it, like he only did it because he felt sorry for me:( I feel like I messed it up, how can I stop feeling bad about it?

The only way to know if he felt sorry for you is to initiate a conversation.

Brad, this is Melissa - we met the other day. Just wanted to thank you for listening to me and to see how ur doing today.

If he responds back, then continue the conversation without mentioning how you feel you dumped all over him.

In the future, when striking up a conversation with someone you don't know, practice discretion. It's one thing to vent when you're upset - but if the other person doesn't know you, this venting may seem like a whole lot of drama.

If you want to text him .. Do it.  You can find out how he feels after getting to know him better.

You showed him an honest and appropriate vulnerability. 

That tends to make us men feel "positively" (a good thing) toward you.

His response does not surprise me.

Contact him if you wish.