Hi Carolina,
you might already know that I also had similar stages with my son, when he was waking every 1-2 hours at night, during the first 4 months. The only thing that helped out of all the things we tried is 'sleep training' at 4 months (using the 'cry it out method', but with a very specific plan that did still allow for comfort/nursing, but making sure that the baby is still put back down to sleep fairly awake), eventhough still he didn't start sleeping right through the night then, but it at least doubled his sleep periods. 'Exhausting' is too mild of a word to describe how we felt then, but more importantly we were extremely concerned for how poor of a sleep he was getting, if he's waking up every hour or two, when instead they need longer consolidated sleeps. (Now he's almost 17 monts old and sleeping very well, both at night and during the nap in the day, and has been for many months now actually, showing continuous improvement since the sleep training).
I know you don't want to consider 'sleep training', but if you're wondering about the 'cause' of this frequent waking, then my opinion (and also shared by many doctors and pediatricians) is that at this age, the baby is waking out of 'habit' (i.e. she's become used to the breast and wants it repeatedly for comfort and help to fall back asleep, rather than doing it herself), and not necessarily nutrition (i.e. she's not really hungry, that frequently). My son is also not a great eater, picky too, some days he'll hardly eat anything substantial during the day, but still he will sleep for 9-10 hours straight, and then just one breast-feeding in early morning, and he will go back to sleep again for another 1-2 hours.
I've also talked to some other parents who experienced similar situations and didn't want to sleep train their babies; the 'lucky' ones said their babies eventually started sleeping through the night around 18 months to even 2 years... others still have 4-year-olds with waking problems in the night.
Good luck with whatever you decide. If you are curious about the plan I used, you can message/email me.
Tatiana