Early sleep regression at 3.5 months?

My baby is 3.5months now ,will be 15 weeks in 2 days... she is a terrible sleeper during the day, but at night once i put her down by 10:30pm ,she gets up only at 4:30 am for one feed and then wakes up only at around 7:30.. 8 am feeds again and sleeps till 9:30am..

But from the past 2 days she is waking up every 2 hours or so.. putting her back to sleep by rocking and patting doesn't work and eventually I have to feed her, I think she is doing this for comfort .

Is this sleep regression starting ealry? Im so sleep deprived as she doesn't nap more than 30 mins at a time during the day.. so am running on low fuel, will this pass?

Thank you