By running slow, do you mean the sense launcher or all apps?
1. Check how much free ram do you have and how many apps are running in background.
2. Reboot your device. Android is still a quite unstable OS and after a week of running, it may start to lag.
3. You can try to clean Sense's cache and data (this will remove all your custom settings, menu folders, background etc., but after I done this once, the Sense launcher was definitely working faster).
4. You may also want to clean android cache, but this can be done only when turning on the phone by power + volume down. Read more about cleaning android cache before doing this.