Hi Mjaz,
I agree with Naomi. We went through the same thing at this age but without the upheaval of a move (or two) and the worry for a new one. For us it was down to a developmental leap and molars. I tweaked and tweaked until i could tweak no more, it made no difference, save for I was an OT mess as well - not great. In the end, i took a deep breath and decide to ride it out. We stuck with our usual routine save fro offering slighter earlier naps and for a tad longer on short nights with a slighter earlier BT. So as a genreal rule of thumb it was something like:
NTS = 10h or less, Nap and 12.30 for 2.5h and BT and 6.45
NTS - 10.5+ hours (very rare at that time!) =, Nap: 12.45 for 2h and BT 6.45-7pm
My DD seemed very frightened at night and going to bed (but not nap time) but it wasn't night terrtors, I don't know if it may have been the molars pushing and the poor little mites just don't get it. It must be scary. I stayed with the where necessary and then to get back on track once the worst had passed used WI/WO. Having always slept independently, it didn't take R long to get back on track. Once the NW had stopped and we just had EW left to contend with, we introduced the o'clock - amazing bit of kit!
I know that you will be worried about your DS. I was so so concerned for R but having read lots of similar posts and BTDT myself, I can see now its just something that a lot of LOs unfortunately go through. It may take sometime to come out of the other side but if you remain consistent so you DS has some normality and stability, you will get through it I am sure.
HTH xx