I have a galaxy s2 skyrocket and it always slows after closing apps.?

[William]

Every time I am using an app, lets take Facebook for example, I would press the home button to get back to The home screen. After I press it, it immediately goes to the background of the home screen then one by one in a matter of five to sometimes ten seconds all my shortcuts to my apps start to pop up... It also becomes really slow to swipe page to page during this period of time. But on the other hand, while operating an app my phone is fast as lightning! Keybrd pops up instantly and everything. Which is probably why this is so irritating. Hope I included enough information!