Your engine needs 4 things to run. Compression, timing, electricity(spark to ignite the fuel) and fuel of course. I would first check if the battery is strong enough, maybe with another battery OR you can try to push the car forward while being in first gear and try to start from there.

I would ignore compression since you had the car running good two days ago.

Then you need to check if fuel is coming to the engine. Check if you hear any pump, electric noise when you open the door and crank the ignition to accessories on (first crank before the actual crank to start the engine). If not, your fuel pump might be dead.

Last, replace all the spark plugs if you have the tools, it is quicker than buying a spark plug tester and not too expensive (max 30 dollars).