Perhaps something is going on in their life. You can't immediately assume for them but I do agree that this is weird and fishy. If this happened, it's hard but you have to try to talk to them in person and confront what they're doing. They deny it? They're not worth your time.
Suddenly they have realised that they are head over heels with you.
Have you tried texting or even writing a heartfelt letter. Has your friend done this before? The bible says that there is a frustrating of plans where there is no confidential talk. . Give your friend time to respond to your letter