Some advise/ help

I need some advise on my 4 almost 5 month old.. I breastfeed her at night and we cosleep.. she supplements with formula during the day when I’m busy running errands or if we’re out and about, she also just started cereal. I do breastfeed her in the day when i have the time. Anyway, long story short- at night she has been waking up every hour to two hours to nurse and I’m exhausted. Why is this?? Is this because she doesn’t sleep on her own yet ? Is there anything I can do to help with this so I can get some better rest? Or atleast try. It doesn’t help she’s a light sleeper either so when I move so does she. Any kind of advise would be great at this point. Thanks ladies