Struggling at night

She always been good at night and slept through from 2weeks, never had an issue, was in her own room from 6mo and her floor bed from 12mo, this past month has been a nightmare at bedtime, she goes down at 7pm every night she used to tell me to go once id tucked her in but now she wants me to stay in bed with her until she falls asleep which can take hours some nights(that part is not what im concerned about) but she wakes me up every night at 12 doing blood curdling screams saying shes scared (shes never had a problem with the dark and always slept in the dark) and asks for mamas bed, so i get her in bed and shes fine but she expects me to sleep on the floor because she doesnt want to get in the middle of me and my partner, these past few nights ive moved her back into her own bed when shes fell asleep, and the cycle of screaming starts again not long after (shes never slept in our bed other than the odd night when ill). Ive tried night light, star projector but when i turn them on she says shes scared and wants them off, i dont know what could be causing this, any advice pls or some possible reasons to why she might be so scared ( she shares a room with my 1yo but hes very much delayed in development and cant be scaring her as hes always fast on when she reacts this way)