Well they do say a drunk never lies so maybe u do have other siblings out there that u don't no about.

She was drunk. Drunk people would say anything. why this is an FML?

While the long lost sibling thing is possible, it sounds alarmingly like a warning sign of Alzheimer's, dementia, or some other brain degradation disorder, OP. I'd keep an eye on her, especially if she drinks on a regular basis.

Do you look like a guy? Maybe she was confused.

currently watching the george lopez episode where george finds out he has a sister so i thought that was ironic lol

I feel those feels, OP.

She might be referring to her pet. If you dont have any pets, she might have obtained a pet like a dog or cat while you were absent and thinks of the animal as a surrogate child. Look for signs of an animal inside your home. She may possibly be hallucinating due to the alcohol

Failed attempt at peek-a-boo?

You know she cares for you, it she meant you!

She probably meant "Where's my little girl?" Meaning she misses the times you shared when you were a child.