Issues with uploading

For the past couple of days, I've been trying to upload things to Soundcloud, Mediafire, zShare, and through AIM and MSN file transfers, but in all of these situations I think that my upload speed mysteriously tanks momentarily. Because of the nature of these services, this causes the upload to either restart or fail with all of these sites. I haven't been able to upload anything because of this. Any idea what's going on/any way to fix it? I'm on Verizon FiOS, Windows 7 32 bit, and I've tried with both Chrome and Firefox if that matters. I can give additional information if it's needed, just ask.

It could be that Verizon is throttling back your upload speed as a sort of anti-P2P file sharing thing.

Well, I *do* use uTorrent for anime, but my download speed isn't affected at all and I rarely leave my torrents up to seed...should I just call Verizon and see if they know what's going on?

Edit: I just tried on another computer and had the same problem. >.>