1998 Camry electrical problem

1998, 4cylinder, 100K+ miles. Engine starts and runs, headlights turn on but everyting else is dead, including rear lights. Will not shift into drive unless I push the hidden over ride button. Drove it to work as is, then 15 mins into journey, everyhing came on slowly, including engine check light. What would cause this. Now alarm system operating, therefore immobilized until I can use transponder (At home of course!).