MRI results

I have triple negative cancer and have had 3 rounds of chemo. Yesterday I had the results of my mri scan and was told there had been no significant change in the size of the tumour. Consultant said this wasn't unusual at this stage and the new set of chemo I'm starting today can change things and that I was to look at the end result of what will be after my operation. 
I'm really quite devastated tho as I had hoped it would have reduced even slightly and now worry that it's not going to work at all. Does anyone have any advice?