One reason might be ..YOu are getting low upload speed cuz You are seeding 5 torrents at a time. So my question to you is-Whats the upload speed yor are getting right now., and whats the upload speed you are supposed to get...?
you can check your upload speed from here
Code:
http://www.testmy.net/tools/test/u_load.php
Another reason might be ..You are not being able to connect to other leechers. So, try portforwarding-->
Code:
www.portforward.com