I really hope it's a phase!!

My daughter hasn't 'slept through,' since about 4mths old, which is no problem, as I don't expect she will just yet, and I've always been able to feed her back to sleep.
Of late, she wakes around 1am / 2am, and feeds, but I can't get her back to he bed no matter how long I sing to and rock her. I'll then bring her to bed with me, which I usually quite enjoy doing, and she'll go back to sleep pretty soon with a bit more cuddling.

The problem is that she'll then wake somewhere b/w 3am and 4am (5 if we're lucky), and cannot go back to sleep unless she's lying right on top of me. Even then, she's still extremely restless, and wakes and cries very regularly as if quite distressed until around 7am, when she finally goes back to sleep exhausted. Unfortunately, I can't sleep with her draped all over me, and the positions she gets into don't seem safe from a SIDS point of view (i.e. head down against my chest and nostrils mostly covered). For the last few weeks I have been living on around 4 - 5 hours sleep a night, and am starting to not cope. Trying to feed her back to sleep during this second bout of wakings has not been successful, dammit!!!

My gut feeling is that it's separation anxiety (as panadol and brauers teething relief haven't helped at all). I want her to feel safe and secure always, but I just don't know how to do this at this time of the morning, aswell as manage to get enough sleep to help me stay sane.

Any helpful suggestions would be greatly appreciated!! My sanity is fast disappearing!!