Sluggish internet connection

My internet connection has been very sluggish lately (I've never had any problems with my connection in over a year and have not changed anything since). I need help figuring out what is causing it. Any time I try to download something it will lose connection and cause my download to stop.

I don't know if this has anything to do with it, but here is a bit of my router (DI-524) logs:
Jan/23/2008 14:01:17 Drop UDP packet from WAN xx.xx.xxx.xxx:5000 xx.xx.xxx.xxx:137 Rule: Default deny
Jan/23/2008 14:01:07 Drop TCP packet from WAN xx.xx.xxx.xxx:5000 xx.xx.xxx.xxx:8080 Rule: Default deny
Jan/23/2008 14:01:05 Drop TCP packet from WAN xx.xx.xxx.xxx:5000 xx.xx.xxx.xxx:8080 Rule: Default deny
Jan/23/2008 14:01:03 Drop TCP packet from WAN xx.xx.xxx.xxx:5000 xx.xx.xxx.xxx:80 Rule: Default deny
Jan/23/2008 14:01:01 Drop TCP packet from WAN xx.xx.xxx.xxx:5000 xx.xx.xxx.xxx:80 Rule: Default deny



This goes on non-stop with lots of different IP addresses and one wierd IP that is always 1 greater than my real IP address e.g if my IP address was 11.11.111.111 then the dropped packet would come from 11.11.111.112. This problem persists even after acquiring a new IP address, reseting my router and modem, and reinstalling my realtek onboard LAN drivers.

I tried bypassing the router and connecting directly to the DSL modem, but I still have the same horribly slow connection.

Edit: This has been happening for about 2 days.