S.H.
if she is cutting molars... those hurt more than regular teething.
There is also a growth-spurt at about 18 months of age... sometimes earlier.
Is she eating/feeding well?
Has she hit any milestones lately or changes in motor skills or cognitive development? These tweak sleep as well... growing pains being both physical and cognitive. If developmental based, then you can't just stop it. It is hard for the baby too.
Is she having "night terrors?" These start to occur too. Look it up online. This is developmental based too, and is normal.
And there is also "separation anxiety" which occurs at different ages and is manifested differently per age of the child.
Crying for 2 hours, is not good. MUCH too long. Not good for their brain either.
I know its not easy... but she needs something, and even if it is comforting, from you, then that is what she will need. Don't worry about creating "habits" now. Otherwise, a baby will not get what they need.
All the best,
Susan