why the hell did season 4 of skins end as a cliff hanger and season 5 started like nothing happened?

I'm wicked pissed about the way season 4 of the uk version of skins
ended, like season 5 was going to tye up the loose ends but it didn't.
season 5 just started with all new characters! season 4 was awesome i
loved it and was reallyyyy hoping season 5 would continue with the
same characters and story line. someone tell me what they thought
about it cuz im pissed lol