Welcome to BB . It is pretty normal for this to happen, I went through something similar with my DS2. Something that worked well for him was to put a musical cot toy with lights in his bed with him. It was a Fisher Price aquarium type toy that had bubbles, etc. I told him it was his special toy, just for bedtime, and he became quite excited about using it. This helped make going to bed time a positive experience for him again. I also told him that if he woke up at night, instead of calling out for me, he could turn his special toy on. This worked a treat, he was comforted by the light that came on and the music that played.

I hope you find something that helps