Welcome to the catnappers club!!
Sounds like she wants to have longer awake times. DD screamed when I put her down after an hour, then started putting her down after 1.5 hours and she went down fine. She's now doing 2 hours up.
She also started catnapping at 3months old. She takes half hour sleeps during the day and sleeps all night. Biggest lesson I've learnt is to go with the flow. If she's happy after her short sleep then just get her up. If she's still tired try re-settling her, or get her up for 10mins and try again.
Don't get stressed if she won't go back to sleep as it can become very frustrating and that just results in an unhappy mum.
My motto: feed them when they're hungry, put them to bed when they're tired and make the most of the time inbetween!

Keep night time quiet and dark and no eye contact.
DD has been catnapping for 2 months now and I've just come to accept that this is how she is. She used to have 3 two hour sleeps a day. Oh how my life changed when she started catnapping!
I still hope one day she'll spoil me and do a big 2-3 hour sleep.

The only problem with the catnapping is she gets very overtired by the end of the day.
Hope things get back on track soon for you. It can be very frustrating this sleep thing.