heh, the cause of the lag was certain wads. I'm not sure why, but they cause my server to lag. Anyways, sorry for the trouble :P. And thanks anyways ^_^
EDIT: Wow, never mind. I added just a few character wads, and it lagged. I even went to a server, then hosted my own with the exact same wads, and it would lag. I'm not making much sense, am I?
EDIT2: YES! I finally stopped the lag! I just needed to forward ports, heh. Anyways thank you all for helping me try and figure it out! ^_^