The 18m SR ime was a tough old time. I found myself constantly questining my judgement, worrying if I was making things worse, worrying that I was creating bad habits and generally really worried for R given that sleep wise she always seem to do so well, and much like your LO, need her sleep to be anywhere the darling she is! Its common. Just trust that you know what you are doing, and if in doubt , check in. Theres plenty of support here for you as there was for and any many others in the same situation.
Big hugs x