My ex is giving me mixed signals!!!?

Me and my ex broke up a year ago and we have talked on and off since then. I decided to text him 3 days ago (Monday) because we hadn't talked in 3 months. At first it was friendly but then he started saying how y i am and how he would like to hang out with me again. We planned to hang out Tuesday and Friday but the day after we texted he was ignoring me in the halls and avoiding me. He texted me after school that day saying he can't hang out because he had a doctors apointment he forgot about but we can still hang out Friday. Then the next day he was still avoiding me and wouldn't text me and i dont know why! He said he wanted to hang out with me but then the next day he was avoiding me and doesnt want to hang out anymore!! Why is he doing this!?? Why would he change his mind the next day and not talk to me?? HELP!!? Tomorrow is friday but i dont think we will hang out!!