How to cope with GOOD BIG changes in life?

I am a very anxious person who likes to be in control of everything in her life. I grew up not having parents or a secure childhood and the minute I became successful and could take care of myself, I felt there a power and I grew out of this.
BUT this year is going to be a big year of changes for me. I am getting married to the love of my life and we are having a long awaited baby together. I have been looking forward to these things happening for a long time and I couldn't be happier. I do feel like, this anxiety is disabling me to truly enjoy these moments. Instead I stress over stressing,future finances,babies health,the delivery, my social anxiety for the wedding ceremony... It just all feels likes it happening at the speed of light and I am not in control of the future being unpredictable. So, whats your best advice on how to enjoy these moments? How do you calm yourself down? What do you say to yourself?