Adjusting Bedtime Suddenly

I just tried setting a new bedtime because my bedtime was getting way too late (8am-10am), and I just couldn’t afford to sleep till 6pm anymore without feeling anxiety about missing the day and commitments. I’ve been using Advil pm and going to sleep at like 11, but I always wake up 3 hours later and have to take that Advil pm to fall back asleep. Does anyone know how long my body might take to adjust to this new bedtime so I can sleep through the night? Are there any tips I can follow to get to the point where I can sleep through the night without waking up?