With a tiny baby like her it is going to be hard. Look everywhere!! Even in drawers. You would be amazed at the amount of stories I have heard where someone opened a drawer and there they were. I have found one in the toilet before as well. If you have other pets watch them closely. They will often tell you where they are. I had a cat that kept looking at me and then down the hallway repeatedly. I took the hint from her and was able to catch the escapee quickly.
Things to try. You can put flour down on all hard surfaces of the floor. If she is on the move at night, you might see where she is going. You can put BLUE painters tape down on the floor sticky side up so if she slithers across it she will get stuck. When I tried this I put it all around baseboards because they generally hug the baseboards when they are on the move. If she gets caught in the tape DON'T PULL IT OFF! Use olive oil or a vegetable oil to loosen the tape.
Most of all GOOD LUCK!!