My little one has been doing the same thing lately when we used to both sleep midnight to 8am. I feel ya and I know it’s hard. I’m a single parent so I’ve definitely had my nights of frustration. The only thing that helps us both is usually I take her in my bed and cuddle her give her her paci and watch those hey bear fruits on YouTube and let the live play all night. But that also only works if you co sleep or think it’s safe for you and your baby. I know when I wrap my arms around her she can’t move without waking me so personally it’s been a lifesaver for me.
It’s a sleep regression - very natural and normal at this age. I found that mine was also coupled with growth spurt and development, so she’d have a bottle of milk and then go to sleep.
This sounds like sleep regression. Their first sleep regression comes between 4 and 5 months. It's a HUGE brain development. She isn't doing it to annoy you. Remembering that can help you stay patient/sane. Are you picking her up for a cuddle? She might also need a bottle of milk/boob, if she's having a growth spurt.