Unexplained lights in the sky, moving erratically and quickly right and left, up and down

I noticed a strange light up in the sky that seemed to be moving very erratic, quickly back and forth, up and down. I called my husband out to look. We stood there for maybe 15 minutes, and within that time there were several more lights just like it on the right and left of the main one that we spotted first. It is a cloudy night so they were moving in a out of clouds. These things were not moving like an airplane at all. They were very erratic, back and forth, up and down. After about 15 minutes my husband and I went back in house.