Can it be the battery if I still have headlights?

Yes, your battery can still be dead if your headlights are coming on. It could also be your starter or alternator. If you hear the car clicking and trying to start, it most likely is not your starter. If your battery cannot hold a charge, it might be your alternator. If you manage to get it jumpstarted and it starts a high-pitched squealing, shut it off immediately, as your alternator might be locked up and that sound is the serpentine belt. If you let it run, the belt might snap and severely damage other engine parts. If it is the alternator locking up, you either need to replace it yourself or get your car towed to a repair shop so they can replace it.