This keeps happening to me today, on several servers. Is just me or are a lot of people getting this?

Also, is there anything I can do to stop it? I've closed anything else that might need to use my net connection.

Might be your ISP or ISP of the server.
What patch you using currently?

W.

It might just be that my ISP is particularly busy - it was just after everyone got back from work on a Friday evening.

IF you are using ADSL then this might be pretty normal especialy if your service has hight connection ratio.