One thing i have learned with lumps over the last month, don't take no for an answer unless they can prove it's something non-concerning. The only way they can do that is to allow a specialist to look at it. They told my wife something similar to yourself.  Her turned out to be the big C. However, the odds are heavily stacked in your favour that it is indeed nothing. So don't freak. 

Let them prove it's hormonal. In the grand scheme of things, 2 weeks isn't gonna make a difference, but by the same token, lumps in the breast should be seen in person and not just brushed off in the hope you'll never need to contact them again. I could see their 2 week thing if it was in the neck.  you know, the usual places things spring up if you have a wee virus or even a wee infection going on, but a lump in the breast, testicle, armpit etc should be seen and not just a wait and see when they've not even afforded you the courtesy of an in person appointment. I'd call them back and insist on an appointment.  Just remind them the guidelines state breast lumps need to be checked out and doesn't mention a wait and see approach. It doesn't even need to be a gp.  a nurse could do it.  It was a nurse who fast tracked my wife.