Svetlio,
Just goes to show you that
demo trading can only take you so far...
It's only when you have your real hard earned money on the line, that you can experience the full affects of trading on your psyche/emotions. It's a whole different ball game.
First off, you should not be afraid to lose all the money you have deposited w/your broker, Oanda. It is risk capital, and should be treated as such. Of course that does not mean that you should trade recklessly w/out care of winning or losing - but just be aware that you most likely will lose it all - especially if this is your first time trading on a live account. If you friend is not aware of this and ok with it, then give him back his money.
Secondly, you need to have some confidence in yourself and your system. This might need to be rebuilt after your recent experience. That's okay. One way to do this is to trade even smaller than you already have, until you have regained your confidence. You might also need to take a little time to refocus, that's okay too.
Treat your mistake as a lesson learned, and be greatful that you're account is still flat and w/out major loss(es). You're most likely in for many more lessons, before you can be consistently successful. Be aware of this, and plan accordingly.
With patience and persistence, there's a chance you will persevere in the long run.
Good Trading,
Sundance