Hi
my lo is now 6 months, but i remember when she was about your's age - she also seemed to sleep all the time and i was concerned -but then without warning she changed at about 3 months - i htink she realised there was more going on in the world and wanted to be part of it.
basically, i think the important thing is to make sure that she sleeps at night. my best tip here is to cut 10 mins off each daytime nap initially and see if that helps. Or take into account the normal 45 minute nap cycle and only let her sleep for 2/3 cycles at a time. I found after a bit of playing around, that if I woke dd at about 2.15mins (3 cycles) she actually seemed to be less sleepy - but it takes some maths working it all out.
good luck and enjoy the sleep while you can - i know you feel you're missing out, but now that my little one only does 2 naps a day, i find that suddenly i understand all those mums with no time!
Jenni