I'm in a pretty bad situation right now. I ran the following terminal commands to upgrade my Laptop from 12.04 LTS to 14.04 LTS, and left my computer to let it sit to do its thing. When I came back, the terminal window that was running the upgrade contained some prompt about installing an upgrade to the package manager. The moment I touched my keyboard to respond to said prompt, the terminal window closed mid upgrade...

Commands I ran:

$ sudo apt-get update

$ sudo apt-get install update-manager-core

$ sudo do-release-upgrade

I'm not to concerned about those, since they were working. Only felt the need to use them because my update manage still hadn't picked up 14.04 by like 4:00PM today and that's the way I know to make it grab it.

How can I fix things and get my system sane again? I'm currently able to use it, it's just the following issues are present:
Any time I try to access the update manager, I see a prompt with the header "Not all Updates can be installed" with details and the options "Partial Upgrade" and "Continue". Clicking continue gets me the following message.

Software Index is Broken:



It is impossible to install or remove any software. Please use the package manager    

"Synaptic" or run "sudo apt-get install -f" in a terminal to fix this issue at first."

Trying to run the mentioned command generates the terminal error:

E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily   

unavailable)

E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?

lsb_release.a lists that I am on 14.04, but I definitely appear to be between versions. I've tried to re-start the upgrade process but get greeted with the same error in the terminal window that I mentioned earlier when I do. I haven't attempted a system reboot, but I'm scared to, since I think it will break my OS.

How on earth can I fix this mess?