Ceiling sagging around our big light. Something to worry about or not?

Hi all, I've just moved back in with family and I noticed the ceiling above my bed wasnt even and had cracks straight down the middle. Decided to have a look to see if it was level and noticed a sag where the light was fitted. Doesn't bounce or anything when I press it, but its been repainted before and the crack came back. Should I be sleeping somewhere other than here and should we call someone to look at it? Based in the UK.