@Kescilly It does sound quite normal, but agree with Spargle about getting checked out if its worrying you. Its likely a drop in BP because of the warmth (the vasodilation), or a little bit of dehydration, mixed with all the weird hormonal stuff going on right now. If it happens again somewhere non- related i.e middle of the street, then thats a little more worrying. But def worth a chat with your mw if you are concerned.
I've had a little bit of 'fainty-ness' feelings getting out of warm baths and needing help to get out. Just managed it REALLY slowly and holding on to husband. I used to get a similar feeling coming out of sauna's and steam room's though, so know its fairly common for me. Having a large glass of water in the bath helps too.
@Napssavelives - your situation sounds horrible right now. I'm so sorry. Hope you can get the right support and he bucks his ideas up soon. 
On the movement front, is anyone getting regular movements yet? I've been getting them irregularly for weeks, might have 5-6 episodes one day, then maybe just one the next. And usually at different times of day too. I know its normal to not have regular movements until 24/40, but I'm starting to get a little worried. Especially with the anomaly coming up and that little thought of 'something major is wrong' keeps popping into my head. Arrrgh! Why do we worry so much? Does the worry ever end with parenting? I thought I would be VERY laid back as a mum, and now I'm not so sure... 