No, you haven't missed 5 seasons. It's only half way through it's first season (13 episodes) and the rest wont start back until April in the USA.
When it does come back, it'll follow American Idol (which I think, is a good decision) but it'll also be directly up against the final season of Lost. I know a lot people who watch both Glee and Lost and aren't giving up the final season of Lost for Glee. Glee need good ratings for it's 'back 9' so I hope it doesn't suffer.
What happened in the ep you saw, Amy?
The last episode I saw was 'Mash Ups'. If any episode in any tv made me a shipper that did. Puck and Rachel were nothing short of gorgeous in that episode.