When I got my first BFP years ago I had no symptoms but just felt different. This time I had heartburn & tiredness about a week after O followed by sore BBs then about a week later when AF was due the urinary frequency set in. I guess what I'm saying is both experiences were completely different. From everything I've read (and been told by doctors) there is nothing you can do to prevent an early mc. I now take mega b & vitex vitamins which are supposed to regulate hormones and therefore help babies stick.