I can't say for sure it's a bad sign but in my experience (I have never had a positive Beta/home pg test) the breast soreness goes away after the trigger HCG shot leaves the body. So I think to start with it is an 'artificial' soreness. Since I have never been pg I always wonder if the soreness would come back if pg is achieved. The temp dip could either be implantation dip or AF coming or just a fluke. I have all these signs every cycle (including mild cramping/ov pain during almost entire luteal phase) and so I just don't even read into them anymore so as not to get my hopes up. Will you have a Beta on 12dpIUI? These next few days are torture, aren't they? Hang in there!