Ipod 5 lagging, is there a way to free up some ram?

When i got it, it ran so smoothly and I was able to jump between candy crush to FB messenger to twitter with no problem but now i cant even get to the home screen without the app resetting. It's like i dont even have multitasking on my device. I'm assuming this is a jailbreak related issue, so im considering restoring as a new ipod. Would this help or is this lagging just normal wear and tear? Its going to be a year that I have this ipod on September 7 and when I bought it, it was running ios 6. something and now its on the latest os. Any help is greatly appreciated.