Well may I say, we all appreciate all the sacrifices you make as a Mom and as a Military member for our Nation.
*Sorry, I misunderstood your posting earlier.
For weaning at night, this is the hardest one to wean from.
If she does not take a pacifier, will she take a "lovey" of some kind? A stuffed animal to cuddle for sleeping? My Son does this and it helps him sleep.
Or, maybe give her a sippy cup of water?
You said she takes a bottle and formula at the babysitter... how MUCH is she actually drinking? You want to make sure she is getting enough intake there. Then, how OFTEN is she being given the bottle? A baby must be fed on "demand" and not on a "schedule"... and still, with formula, it should be every 3-4 hours or so. *For the 1st year of life, a baby's PRIMARY source of nutrition is from breastmilk/formula... NOT solids.
And, she should be offered her bottle FIRST, before solids (if she is on solids yet). I would check and make sure your Sitter is adequately feeding her the bottle.
Next, she probably does NOT take a bottle at night, because you are there... she wants YOU... and to nurse. She misses you. And this is normal. BUT, if you do not have enough milk, then she won't be getting enough even though she is at the breast often. Also, at this age, they start to get "separation anxiety." So, there is also all their other developmental phases intertwined into it too... and ALL babies have variations in sleep and phases.
BUT... I would make extra sure she is getting enough intake during the day when she is at the sitter... PLUS, make sure she is getting enough intake from the point at which you are home with her. And just nurse her every hour even, before bed... if this is what will "satisfy" her and keep her tummy full before bed.
Give her a good long solid nursing at night, just before bed. Or, even supplement that with formula, since she is used to taking this the rest of the day.
Or, cluster feed her from early in the evening before bed, so her tummy is full.
Usually also, they will wake more if they are going through a growth-spurt or developmental change...and they will naturally get hungrier and more often, and need more intake because they are growing. The bigger they get, the more they need. This is just a normal natural occurring thing and you can't "stop" them from having growth spurts and "needing" more intake, even at night. I fed/nursed my kids on demand for the first year.
I know in your situation it's hard.. .but your baby probably is not ready to stop night nursings cold turkey....
Also, is she getting her naps at the baby-sitter? Naps helps them to feel more settled, and less over tired at bed time.
Also, maybe since she is just down to one nursing at night, and has formula during the rest of the day.... MAYBE your milk output has lessened... and so even if she's at the breast, she is not actually getting any or enough intake? Perhaps this is why she is only sucking for a few minutes, because it is not a "productive" nursing for her, but still waking up a lot at night.
Then there is other thing... where does she sleep? In the crib? Sometimes, as a last resort, a Mom will co-sleep with their baby just to get more rest... since babies often sleep better next to their Mom. BUT... this is a personal decision... and you need to make sure this is a "habit" that will suit your situation.
Not all babies "know" how to self-soothe... other than being next to their Mom. My daughter was like that, but my son is more independent and could self-soothe with no problem. Each baby is different.
You'll get lot of ideas here... all the best to you,
Susan