Without noticing, I filled up my wordpress database and since I don't have an unlimited size, my host put it in 'select-only' mode.
Trouble is nowhere in WordPress I could find what was wrong !
I didn't get any errors saying 'unable to insert' or whatever.
Only message I got was 'Send for review' on a new post instead of 'Publish'.
I only figured the problem once I logged on my host.
Any verbose in wordpress would be much appreciated !