Big Hugs to you!!
My stepdaughter has this problem with her lo (13 months) so I posted a similar question for her as it had got to the stage that it was a running battle to get the baby to bed in his own room every single night.
The replt I got was that consistency is the key - have an established routine and strategy for dealing with this. My own lo is four months old (yes, nearly a year younger than his nephew, it gets confusing!) and his bedtime routine consists of bath, dressing in pyjamas, bottle in his dimmed nursery and then into his crib, so he knows its time for his "big sleep".
My stepdaughter does something similar, after his bath her son has "wind down" time in his own room with a bottle and story.
What I was advised was whatever technique you use ie Walk in Walk out, PD (but not CIO or CC) you might have to persevere for up to two weeks before improvement is seen - this could mean a lot of tears!
Good Luck, you'll get there in the end