Hi
As you probably know there is tons on here about 45 minute naps. My lo went down to 45 minute naps at around 10 weeks too, she's 4.5months now and has just started taking longer naps.
I tried waketosleep and other methods of extending naps, never worked. With hindsight - and from reading everything I could get my hands on - I realise that these naps were perfectly normal and developmental for my dd. What I mean is up to 10 weeks she was tired out from being born basically! Then at 10 weeks she seemed to realise she was here and alive and became more alert, however she couldn't actually do much to tire herself out and so could only sleep for one sleep cycle.........Very trying indeed especially as it became harder to settle her as the day wore on and she was often hysterical come bed time.
However as soon as she found her voice and started babbling she started to extend her naps, then when this didn't wear her out she went back to 45 minute.........then when she started rolling over she started extending her naps then when this bored her she went back to 45 minutes!!!! Now she is working on sitting up, pulling herself up with all her might - and guess what? She's taking longer naps again!!
I've learnt to ride it out and if it gets too much when she's 45min napping we go for a care or buggy ride.
Another thought.........Mia has never had a long morning nap. I'm not convinced that after 12 hours solid sleep she need a 2 hour nap after being up for 2 hours so she just has a 30-45 minute catnap. Then she takes a longer nap at lunchtime as she's really ready for it (it's based on gina fords routines and seems to fit in better with her natural biorhythm)
then another wee catnap around 5pm as she's doing now. Doing it that way also reduces the anxiety everynap time - I now just worry about the lunchtime one!!
HTH