I know why your macbook air is happening something like that.
there are 2 reason that migh cause your Macbook air can't wake up after sleep..
1. when you close the lid of the macbook air, the logo light(screen) turns off, you might think your macbook air is in sleep mode, but actually not, your mac is still working, and it was trying to sleep, and it take about 5 minute if your work on your macbook air very hard like processing big game or application to actually turn to sleep mode, and when you try to wake it when it is trying to sleep, it don't know what should do so it turn to like some "stupid" mode
2.your software have problem, when i say software i mean Mac operation System(Mac OS), try hold Comman-Option-R when you are booting your computer, then it will led you to reinstall your OS, it take some time to download the system(about 4hour)
I hope i help you...= =