The best advice is to remove mirrors from your bedroom - even the little ones. Mirrors bounce chi around, which can disturb sleep. They also represent the element of water, and one solid feng shui rule is to keep all water elements out of the bedroom, including mirrors or pictures of water lest the water douse the element of fire, which you'd like in a shared bedroom if you want to keep passion alive.
Likewise, feng shui wisdom suggests if you have a mirror that reflects your bed in a marital bedroom, it is like inviting a third person into your relationship. If you're into that kind of thing, no worries. However, if you're not, keep this in mind: feng shui wisdom suggests a mirror reflecting the bed could cause infidelity in a committed relationship.
I've known these mirror rules of feng shui for quite some time, but sometimes I play fast and loose with them because I believe I can adjust the energy in my spaces using other methods as well. Until just recently, I had a jewelry cabinet with a mirror on it in my bedroom simply because it was the only place I felt there was a good space for it near where I got dressed.
Recently, we had some visitors from another realm come into our house with some off-putting, heavy energy. I'm not a fan of uninvited spirits hanging out in my home so as soon as I became aware of the energy, I did an energy cleansing. As I was walking through the bedroom with my palo santo, this cabinet that has been there for a few years started to give me a really bad vibe. I felt impelled to get it out of the bedroom right away. Now it hangs around with the other water elements in my bathroom. Problem solved, and perhaps not surprisingly, I've been sleeping better since its removal as well.
There is an exception to the no bedroom mirrors thing. You can have one on the inside of your closet door, but keep the door closed.
If you're struggling with sleep or the energy in your room feels off, try covering or removing mirrors. There's a good chance it will allow the chi to settle, and you'll sleep better.