Should I do something, or wait it out?

My son (19 months old. actually almost 20) has been having trouble falling asleep for a few weeks now. At bedtime it takes him nearly an hour. If his sister is at home (two days a week) it takes at least 45 minutes to get him down for a nap (with multiple tries), or he skips it all together.

He has been having a bottle right before going to sleep. He used to fall asleep/get very drowsy with the bottle, but lately he's still wide awake. On the days he goes down for his nap well I sit with my hand on his back for about 10 minutes until he's asleep. At nighttime we just leave him up there he talks/cries a little for about an hour before falling asleep.

I should probably bottle wean. Will that help? Or does it not matter, and its just a phase?

We put him to be at 7, he usually wakes up around 6:30. I start trying for nap at noon, he usually sleeps about 2-2.5 hours on the days that he actually naps. Today is not one of those days.