Four month sleep regression?!?

The other day I posted an answer to a question about someone asking how much their four month old slept, I said my little daughter slept from 9pm until about 7am....I spoke too soon ARGGHH! The past three nights she has woken a few times during the night and last night it was nearly every half hour! She went to bed at 9pm and woke at 11.30pm, 3am, 3.40am, 4.30am, 5.20am and at 6am I got up and gave her a feed and she fell asleep again until 7.30. She wasn't crying at any point, just talking to herself (well you know how babies talk!) so I don't think she was hungry, I'm sure she would have let me know if she was! I'm just wondering, should I feed her during the night again if she wakens, say around 3am and has anyone else gone through this around 4 months?? Look forward to reading your replies.