Immediately phone CancerCare and make an appointment to speak with an Oncology Social Worker asap! She/he besides providing emotional counseling for Cancer patients should be familiar with what to do re applying for insurance (possibly whether you're in a position to qualify for medicaid). There are programs from different pharmaceutical companies (you may have even seen Astra Zeneca advertise on television that if you cannot afford your medication [and they manufacture it] to contact them to see if they can help. They do that. There are also references listed on the lower right corner of this page that may be helpful to you. Also check with the Social Workers at the hospital/institution where you've been having treatment.
When you mention losing your health insurance, it can be from a variety of reasons. Remember if you have quit or were fired from a job recently, you should be eligible for COBRA which though expensive will still offer you the same benefits you had when you were employed (except you pay the premiums).
Wishing you the best,