it is not reccomended because it can elevate your body temperature, as you mentioned and this can cause foetal distress. i had no idea about it in my first pregnancy either and only found out this time when a friend who had just had a spa put in, read it in the info booklet! i'd had ton's of hot baths and showers before i knew that.
i can't remember whether you said you'd felt baby move yet or not mrs frantic, but if she's still kicking away i don't think you've got anything to worry about.
if in doubt, ring your midwife hun, thats what i do... for every little thing! she could probly visit to check the heartbeat etc for you to put your mind at ease. let us know how you are
Edited by caraMel