Hi, I'm on Cox and BTW, welcome to TechIMO.
This happens to me occasionaly. You might try unplugging the power to the modem for about 1 minute, reboot, and re-power the modem while the machine is restarting and see if you get any improvement from the resetting of the modem.
Here is a site where you can test your speeds. Report back to us your results both before and after. BTW, you're only allowed 3 tests per day at this site so don't get carried away.
http://www.dslreports.com/stest
I use the LA site for my test.
My speed now is 3090 kbps down and 219 kbps up.
Bill