Maybe it was just a really bad day and he just needs a bit of time to himself, I'd leave it and let him get in contact with you. If you have to worry about whether everything you say is going to upset/offend/bore him though then it's more effort than it's worth. You didn't say or do anything wrong. If he's really a good friend then give him a bit of space and he'll come back to you and apologise and say it was a bad time - he needs to apologise I think as he shouldn't be taking it out on you. Remember this is someone that you've only known a month, don't let him affect you so badly. Distract yourself by keeping busy and seeing other friends and don't get too dependent on him too fast or you could easily end up with your heart broken.