I've never seen that problem before, Probably your session time is set something really low (that can be your logged in session time).
Ever since I entered this forum, I never changed that option, and is "signed in forever" so I don't think that's the problem.
To flush DNS, open command prompt(cmd), type ipconfig /flushdns amd click enter. Reboot your system and check if it persists. Hope either will solve the issue.
Thanks for your help. I tried restarting my modem and PC, and I even used a VPN service just to continue browsing, still the problem persists, but not too often with the normal connection that my ISP is providing. I'll try flushing my DNS and see what would come out of it. Btw, what will happen if I flush my DNS? I never heard of such a thing before, as I'm completely ignorant of these things.
http://superuser.com/questions/235749/what-does-dns-flushing-do
Edit:
I've never seen that problem before, Probably your session time is set something really low (that can be your logged in session time).
If logged in session timeouts, he will be logged out but AFAIK in this case, OP is having session timeout for posts.
Already flushed the DNS and rebooted my system. Hopefully this could help me in my problem. I'll wait for 20 minutes and see if I still get the same problem that I encountered earlier and yesterday. Thanks for the help, Muhammed Zakir.