Check your gfci outlets to see if any tripped and reset them.

Father of two, Why do you assume that the lights are on a GFCI circuit. Lighting does not require GFCI protection.

Lenap

When you replaced the <Lights (sorry for the typo)>, what wires did you reconnect to the new receptacle.

When you open up a receptacle you would find a two wire connection at the end of the circuit.

If you found a four wire connection, then the receptacle is part of a continuing circuit.

It is not uncommon for a branch circuit to supply multiple rooms.

I'm with Don on this but think he meant to say light fixture not receptacle