help!!!?

Over the last couple days my 2000 306 meridian has been stalling, cutting off while Im driving, I thought it might be a clutch problem but today when I went to get in my car, the central locking stopped working and warning lights were flashing, this is before I put the key in the ignition, I checked the battery terminal to see if it came loose but it was fine. I attempted to start the car but nothing happened, it wont start, interior and exterior lights not working and I cant lock the car :( What do I do, can someone please help me?