Why is my iPod touch (4thg) so laggy!? Too much music?

I bought a 32gb it ouch so that I can have a lot of music, I have 3,700ish songs and a good amount of apps. Ever since I updated to the last two latest iOS firmware a my iPod has been lagging a lot. What I do is reset it and its fine then, after a couple days it starts lagging again and I reset and have been doing so since its started lagging since the last two updates. My iOS device Is up to date btw And I have like 4-5 gb free. I HAVE NEVER JAILBROKEN NOR IS MY IPOD JAILBROKEN. Should I downgrade or do I have too much music? And also I have gotten all my music from iTunes, Amazon and my a lot from friends who also get stuff from iTunes and amazon.