Do your boobs usually get sore around your period? You said it started today, so it seems to me that that is really likely to be the cause. I know it’s different for me every month, some months I have no breast soreness around my period, other months it can literally be for 2 weeks before hand! I know the pains youre talking about, even a sharp pain here or there. I think it’s good you made a doctors appointment and it is really easy to get stressed out about things like this, I do the same thing. I think you are being kind of paranoid about it though, and you probably won’t be able to knock it off til you get to the doctor. But I really don’t think you should be worried. I’ve experienced similar things and it generally ends as my period ends. Also, don’t underestimate what a badly fitting bra can do to you as far as comfort is concerned! You said you gained a little weight and it hasn’t been fitting as well as before, over the course of time I feel like that could definitely make you uncomfortable! So perhaps a combination of things, and especially your period, have all culminated in sore heavy breasts. Also, the internet has a rich history of making us paranoid about our illnesses. I would stop googling it if I were you, that will probably help. Hope you feel better about it.