I'm also dealing with this myself right now. (There was construction in the space below, and I guess mice got into the walls.)

my problem is not being managed ideally, so i am moving out. i in fact just heard a squeak.

here is my experience...

live traps didn't work at all.

poison stayed untouched for a long time, weeks. i see now that some of it is gone, so something is eating it. however, i still hear squeaks at night. i have yet to encounter a mouse body. apparently if they are poisoned, they hide in their nest and die there, there may or may not be a smell, one never knows if they're gone.

snap traps are supposed to work very well... i couldn't bear the thought of seeing the blood or cleaning it up. or a mouse being partially trapped and surviving with an injury.

i used an electronic trap... it worked, on one mouse... i felt sick knowing i killed it. i set a trap and killed a living thing that didn't mean to do anything to anyone, it just wanted to eat and live... even though i didn't have to handle blood, seeing its dead body, putting it into a bag, throwing it out... all that was still fucking awful. i apologized to the mouse when i put it in the bag, as if it mattered. i still feel terrible about it.

but, they are unhygienic, spread disease - hantavirus... it just has to be dealt with. i think the exterminator should be the one to do the job, they signed up for it. (my landlord won't call one... and is out of the country...)

as far as what you can do in the meantime, just continue to keep things clean. i bleach all surfaces every few days, wearing a mask. the food stays in the fridge. i actually packed most of my cooking gear away except for essentials. i cleared out and reorganized my closets and got rid of a ton of stuff to avoid giving them little nooks and crannies for hiding.

i read everywhere that a cat is best, but my lease prohibits animals.

It's disgusting and awful and you feel invaded. but... keeping things clean will protect you from the actual risks. the exterminator will come soon. and if it helps for sleeping - the mouse doesn't want to be around you. it's more afraid of you than you are of it (like a mouse ;) ) .you probably slept with the mouse or mice in the place many times before you were aware of it. the only difference is that now you know it is there. nothing happened to you while you slept. it is ok to sleep.