Hello Moongirl! Welcome to the HCA!
How many inches of substrate do you have? The HCA recommends a minimum of 6" or three times the height of your largest crab (whichever is deeper wins). The substrate should also be sandcastle consistency.
How big is your tank? How many crabs do you have? I personally like 1 crab per 5 gallons for small to medium sized crabs. If both of those conditions are being met, then you have nothing to worry about. Relax. It is easy to worry when you are new to crabbing! Crabs dig down to chill, destress, and to molt. The time that it takes for all of these things depend on the individual crab. Make sure you provide plenty of calcium and protein.
If you would like to fill this out, we can check the aspects of your tank to make sure everything well
viewtopic.php?f=27&t=46102
In the meantime, check out the care guides, they are extremely informative. We are here for you!

Your other crab will not be lonely - they are able to communicate with each other even though they are under the sand!
