5am wake-ups!

My Dd has been sleeping through the night since 7.5mths. She has always done approx 7pm(ish, generally between 6.30 and 7.30) to between 7am and 8am, usually 7.30.

Recently she started waking earlier but I thought it was in the lead up to daylight savings. Recently however she has been waking and grizzling at 5am and then going back to sleep until about 6.15am.

She has been sleeping more in the day but I don't seem to be able to change that as when she needs a nap she REALLY needs one (e.g. cries, rubs her eyes, keeps falling over etc). Yesterday she slept 6 hours in the day but that was an extreme...it is usually 3.5hours.

Any ideas? I'm wondering if it is teething pain disturbing her?