Does this mean she isn't interested anymore?

This girl and I used to always flirt with each other on MSN and Yahoo Messenger. We also flirted alot during school. But then on Yahoo Messenger we had a group chat and this one guy who is a friend of both of us said “It seems like you guys have crushes on each other and secretly like each other since you two are always flirting”. After this her and I stopped talking for the rest of the day and said nothing after our friend said that. Then the next day, I IM’d her on Yahoo Messenger and she replied, but did not flirt back with me. We had a conversation for about 40 minutes and we did not really flirt for once. Later on that day, I texted her and she texted back but every 10 texts I sent trying to flirt with her, she would flirt back on only 2 of them. She replied to my texts saying “Cool, lol” or “Funny, haha”. If she didn’t say those she would be like “Really, or why?” if I said something interesting. The point is now I feel like I have to keep the conversations alive when I text her and she rarely ever flirts back with me. Does this mean that she doesn’t like me anymore or that she’s not interested?