Why do I keep having to refresh Bittorent?

Let me prerequisite this by saying I am tech stupid.

With that said:
I’ve be
en downloading some rather large media files on BitTorent (for OS X). The downloading’s going well but the annoying part is as follows:

Every time I check on the files (I have 4 going at once) I need to refresh them because they’re going at 0.00 Kib/S. Then when I refresh them everything’s fine. Another hour or so later I need to do the same thing.

The other night, however, I left them alone all night and they were still going when I woke up.

Also, it’s not peer related. Sometimes I’ll have 2,3 or even 4 peers and still be getting 0.00 KiB/S.

Anyone have any advice?
Thanks