My minecraft is messing up badly. When I start it up, it won't connect to minecraft.net. sometimes it says it straight away that it can't connect, sometimes it takes about 5 minutes to load, before saying it. the thing is, though, it doesn't let me click 'play offline'. instead, under the icon, it says '(not downloaded)'. obviously I've downloaded minecraft and everything with it, I've shut down my computer and started it up again, but whatever I do, it won't let me play, online or off. any help?