xkatyx I think that worrying about the birth is perfectly normal, but try to stop if overshadowing your enjoyment of having DC3. Afterall, you've managed 2DC without dying. I think that being with your sister has had a bit of an affect too.
Please give this number a call, you can talk to a fully trained NCT Antenatal Teacher about your worries:
Pregnancy & Birth Line - 0300 330 0772 9am to 8pm, Monday to Friday.
You can call our Pregnancy & Birth Line if you have questions about issues relating to your pregnancy or birth, or if you want to chat about your experiences with a fully qualified antenatal teacher.