Found lump

Hi I have found a lump the size of a peach stone not to say I am mortified to have not found it before it is under the breast. I have had trouble with the same breast before with a bleeding nipple. I have seen my doctor and she has told me I have to wait until I have my next period then to ring and she will refer me I have only just finished my period but she's said it's protocol I am at my Whits end with worry is this correct.