help!

Has anybody ever had this happen to them before? I am 21 weeks pregnant and for the past couple of weeks I had a random spot on my breast that was itchy randomly. Last night it broke out into this. My appointment with the doctor isn't until a couple of weeks and the doctors office said it's too far from now and that I should go into a hospital to be safe. But I feel silly going just for this as I have no other symptoms other than the random itching. I haven't been scratching either so I have no idea were these spots came from! Any help? :/