You may have accidentally closed the latch on the door with the door open, so it is partway locked.
Look at the door lock (on the door). There is a little lever that snaps down (or up or up and down both, two parts) over the bar on the door frame. If this is flipped over, the door is partially latched and the lock won't work, nor can you close the door, it will simply bounce off the latch bar.
To fix, just pull the door handle and use a screwdriver to flip the latch into the correct position. This may restore things.
Otherwise, I'd suspect a loose or broken lock actuator. You will need to pull the door panel to get to that, and I don't know how your's comes off. Do a search, someone else may have a description.
HOpe this helps!
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!