Completed uploads are automatically cleared by default in the Monitor Tab. See the Options->Uploads if you want to change that setting.

Also, the Library->Shared has a column to show uploads attempted/chunks completed. You can click that column several times to sort by descending order, and thus see if any have gone through in the current session.

Or, if your files are in demand, maybe your uploads are being blocked by your firewall? Router? ISP?