I've just found out I'm preggers (5wks), we are so excited but this morning I realised I'm supposed to running a half marathon in September. This is a problem as I've been mentoring my dearest friend into running it as its a huge goal for her. Now I'm going to have to let her down. I just don't think I can maintain the training and run 13miles with how tired I am. Would it put a risk to baby's health? Has anyone run whilst 5months? Should I just walk it?