Sorry, but your situation is not an emergency. Most lumps are not cancer.
Get the mammogram, bring a friend if you need to. Insist (to insurance/MD/whoever) that you want a 3D tomosynthesis mammogram, and ask for it to be read while you wait. Some breast centers do this. Do this now, do not wait. Even if you had been approved for the expedite, it wouldn't have meant that your husband would be here tomorrow.
Do not wait "a few months."