Left the key accidentally

So, i just got a new house with a garage (woo hoo). I was going to arrange the garages stuff, and didnt feel like starting the Scamp.

So i unlocked the steering wheel and rolled it out of the garage, the driveway slopes.

After 4 or so hrs of doing that and some other house stuff i was going to put the car in the garage again.

I accidentally had left the key on and the battery was really low, almost didnt start the car.

Now, i get in this morning and the fuel guage seems not to work. Now, it may be stuck, since there was about a 1/4 tank and the sending unit is in the front of the tank, but i tried hitting bumps on the way to work and nothing happened.

Would leaving the key on fry the voltage limiter in the cluster? There is not a fuse in block that controls the gauge is there? If so, is it seperate from the instrument lights?

Just wondering where i should start first. I was planning to drop the tank to fix a leak in the seal for the sending unit, which i havent dont yet.

Thanks