Think my friend has a crush on me. Everytime girls in the group flirt with me she gets moody. How do I play the situation? Hard to talk to her when she's moody.

Title says it all really. Think she likes us but because she's a friend she always hears what I'm upto with girls. Lately everytime she learns somthing or sees flirting she gets moody with me. Pretty sure she likes me. Just don't know what to do with us being friends and with her acting moody everytime I get attention elsewhere.