Have to stop pumping

I'm have a 8 month old that I have been exclusively pimping for. I am currently pregnant with my 2d baby and because I'm high risk my dr wants me to stop pumping because of the uterine contractions it causes. With that being said I'm so heartbroken over it and have even considered not doing as she asks. I'm very emotional over it and feel sad for my son. I currently started the process of stopping and am at pumping once a day in the am for a few day and then stopping all together and hopefully I won't get mastitis or something. Do you mommas have any tips ?