Recently outside light went out, not the bulb, so bought a new light, not the light. Put old light back on and rewired single pole switch... bingo lights work... lost half the power to my living room after this? What happened? Checked all gfci, checked and reset. Breakers have been reset... what next?

FYI... got 3 black wires coming out of wall where single pole switch is.

Thanks

Check all connections in that box. Could be the hot or neutral.

Swapped wires around now lights in living room work off switch(didnt before) and outside light doesn't work

I would probably disconnect all connections, Then determine which is the constant hot, which is power that carries on, possibly to another switch for LR lite, and which goes to the light. Then make the connections.
A whites likely tie together, one of the blacks should go to the light, connect to one side of the switch,
Then tie the other 2 blacks together with a short piece of black wire wirenutted on, and coonnect that to the other switch terminal.

Got it fixed... turns out I had 2 neutral wires with no ground...