2.5 sleep troubles

Hi I have a long story but I'm really stuck on what to do. We recently moved interstate 3 months ago, my inlaws stayed for a month and my 2.5yr old son did so well with the change. But about a week after they left he started to go downhill. Waking through the night, screaming when we first put him to bed so we left the door open. Previously an excellent sleeper and always had to have door closed. Because he screamed every time I put him to bed I've now got him in my room with a mattress on the floor for the last 3 weeks because I felt bad for him, and it's all still the same (waking through the night, still having to sit with him). We've had to put a gate on the door because he would keep getting up. I've got a night light and put glow in the dark stars in his room. He's super clingy, won't play on his own I have to sit with all the time... Can anyone help please