Hmm, I don't know but I would guess the upgrade process messed things up for
you. You would have much more info and maybe prevent this in the future if
instead of using synaptic you used apt, the terminal in my experience really
gives you more info on what's about to happen and the possible issues you may
encounter.
I can say only: it's a mess.
If I were you I would backup my data and do a complete reinstall of the OS,
which will take you a couple of hours. Or you can try and fix it (which may
take days and weeks, good thing is you'll probably learn something in the
process).
That's my 2 centavos. Hopefully you'll have better centavos from someone else
here, if you are willing to wait and pray :)
