As far as sepration anxiety, you toddler is at the age where separation anxiety actually starts to heigthen. So sorry! There isn't much you can do but to be there and encourage independence and independent play. Reassure her that even if you're in the next room, you'll be there when she calls out.

Its hard to tough it out sometimes.  You dont want to leave her and cant bare to listen to her crying.  Its the old saying ' you have to be cruel to be kind'  By that I mean try not to give in too easily.  Also it surprising how litle things can affect children and perhaps somewhere in her mind she is thinking about the new baby.  I agree with the others and perhaps some new stories at night or a new special game that you both play b4 bedtime.  Having said all of that it could just be a phase and will pass.  Its so hard to know what to do for the best.  If only they gave out instruction manuals when children come along but if they did that then we would have no reason to talk each other on this site.  Good luck with everything.

Kastol

My daughter at that age used to be clingy aswell. All that i did was tough it out. I spent just that bit extra time with her and gave her new things to do, and things like that. Hope this has helped.