Thank you for all the replies and comments everyone, feels great having support!
Day three and I have woken up this morning feeling pretty good, I couldn't quite work out why I felt better but then suddenly it dawned on me -no headache! Hooray!
I did have a little 'woe is me' moment to my husband last night basically questioning if this is the right time for me to focus on myself. It is school holidays here in Aus, I have four children (8,6,4 & 1year old), no family support except for my husband who is awesome thnakfully, no time out what so ever from my kids and generally overwhelmed with my 15 month old who is very clingy and hard work BUT I've started now and I am going to have to make it work. Any tips for success with a young family?