I did a pergola in xmas lights. I have about 10-13 strands all hooked together. They are also all hooked to one electrical extension cord. The fuse hasn't blown, but the whole entire pergola isn't working.HELP!!

Tripped GFI?

10-13 together is quite a bit. They are not one into the other are they?

"fuse hasn't blown" are you sure, did you test the outlet and the extension cords for power? Each strand has two very small fuses inside a trap door of the male end of the string, open and test each fuse starting nearest to the outlet. 10-13 strings all strung on one line is not too much for a normal home circuit but it is too much for those two little fuses. Most strings tell you how many you can connect, never seen 13

What kind of lights are they? And how many on each strand?
Either way, that sounds like a lot of lights hooked together.

If they're the big C9/C7 lights that's around 175 watts per strand of 25.
If they're mini lights it's usually around 40-60 watts per strand.
No idea about LEDs, I think those are the only ones with which you can connect more than 5 together.