This is usually a symptom of a network problem. Since SE's servers are in Canada, your network data has a travel a bit further than in other games with closer servers... and certain ISPs (Like Comcast) have been a bit notorious for causing problems. Other things you can check, make sure nothing on your network has big downloads going, has been infected with a virus that might be using a lot of the network, etc. If you're using wifi, ensure there's no interference (but if other online games are working fine there probably isn't).

But pretty much for this you want to be looking at network stuff.