How to make things right between us?

im i with a girl. She likes me too. we kept meeting eachother in gap of like 3/4 months coz different city. Last time we met was when i went to her city to see her and during that time we were not that happy like before. Me , her and our friends went for a tour during this time.She wad irritated by every single things also she was on her period. Everything was so good when she came to visit me just 1 months ago. So when i came back i talked with her and she said she didn't felt anything this time and it was good when she came to visit me. And Now its all gone. What can it be? What can i do in this situation.

Well, what's going on in her life? Is she dating anyone? Does she have any problems or issues? How are you acting? Are you picking fights with her? Do you take her out for dinner and a movie when you see her? What do you do together? What have you said to her? What has she said to you? I have a feeling there's a lot of things we don't know and we need to know before I can advise you.

It sounds to me like she's probably losing interest, OP.