I Am Really Exhausted

These days, I have been so terribly exhausted at the end of the day that when I put Baby C to sleep at around 9:30pm, I would doze off first before her. For the past few nights, I told myself that I will put her to sleep and once she'd dozed off, I have to wake up to get some work done on the PC but that never materialized coz I slept along with her. I even switched on the room light to prevent myself from dozing off but my battered body and mind were just too jaded and I just fell into a deep sleep. When I woke up last night, it was already 2ish am and I was so dead beat that I could not even bring myself up to shut down my PC. Nonetheless, I still forced myself up to change and sniff Baby C's soiled diaper. I have been waking up every 1-2 hours every night for the past 7 months just to change Baby C's diaper. I wonder when I can ever have uninterrupted sleep and just sleep without any worries from night to morning.