turn the breaker off and then back on again. maybe it is tripped?

When you turned off the breaker, did you move it all the way to the far side? Many breakers typically need to be moved to the full off position and then to the full on position. In any case, just try it again.

What work did you do when you had it turned off? Start there looking for your problem.

I tried several times on and off, but the power is not back. What else can I do

Move the breaker handle hard and fully to the "off" position. Then move to "on".

Yes, now I got the power. Thank you ALL very much for helping

So, chueh, it would be helpful if you tell folks how this got fixed....