BABY NOT SLEEPING WELL/NAPPING

my lo is coming 5 months in a few days & she has not been napping well. I can clearly see that she is tired but we tried EVERYTHING. changing diapers, dark room etc but she is not sleeping. it is so hard to get her to nap/ sleep. is this a sleep regression? other than that she is not cranky at all she just wants to play. i am so dead tired & i worry she’s not getting enough sleep. she used to be able to sleep from 7pm-10am (with motn feeds) but now she has been pushing back sleep & only slept 11pm-7am. what is with the sudden change in sleep pattern. i cannot keep up😐😐😐