In addition to the other suggestions:
at each age juncture, a child still needs to 'bond' with their Mom. Not just as a baby. At each age, 'separation anxiety' and the need to bond are expressed/manifested differently. It is normal.
Also, he is at a 'growth-spurt' period. So hunger increases. A growth spurt occurred at 9 months old, then 12 months old, then 15 months old. Every 3 months is a 'growth-spurt' period in a child/baby. So, if he started this at 9 months old... that was a growth-spurt time for him... and if not getting adequate intake, daily, then their intake is not keeping pace with their nutritional and intake needs. 3 months ago, when he was 9 months old, is when you weaned him. He seems hungry.
Also, maybe he is teething?
Also, at each age change, a child goes through tweaks in their sleep. It is a phase and as they hit milestones and developmental changes in cognition and motor skills.
Also at this age, "night terrors" usually comes up. It is normal. Look it up online.
They are going through MANY changes at this age. They can't help it. Nor can we extinguish it because it is developmental based.
Does he have a lovey? A night-light?
Does he still nap? Because an over-tired child, actually sleeps worse and has a harder time falling asleep and staying asleep. Kids this age STILL need to nap, daily.
And before bed, allow him to wind-down first. My kids take about 1/2 hour to wind-down before bed. It is a part of our routine. And we make things all quiet... before bed.
all the best,
Susan