I am exhausted and worn out, I need some advice please!

So, we recently took my son's nuk from him and he was doing great. He goes down for naps and bedtime with little fussing, BUT he doesn't sleep nearly as much anymore. Before he was sleeping a consistent 7:30 - 7 at night and still taking a 45 minute nap in the morning and 1 1/2-2 hour nap in the afternoon. Now, we put him to bed shortly after 7 but he doesn't fall asleep until 7:45 or 8 (he talks happily to himself) and has been waking up at 5:45 or 6, refusing his morning nap and only sleeping 1 hour if we are lucky in the afternoon. All I can think is if this is all because of the nuk. He is usually overtired by bedtime and nap time, but is surprisingly not terribly unbearable. I mean, he is not himself but not awful all day long.

Any tips? I am exhausted, not sleeping well to begin with, and I just want him to sleep! Is this all because of the nuk?

ETA He is 16 1/2 months old