rainbow on the wall at work today

i saw a rainbow at work today and it stayed on the wall for a couple of minutes then disappeared completely. there was absolutely nothing inside and outside of the building that could have caused the rainbow or any type of reflection on the wall. has anybody else ever had anything like that happen to them before and what happened afterwards? going for surgery friday to check left tube and been trying for 3 years for #1 with my husband. i've never ever seen a rainbow at work before and when i say it rainbow baby popped in my mind. don't know why i even thought of that.