Only prescribed 3 pills

So last week my doctor prescribed me Xanax for my anxiety but he only prescribed me 3. I developed postpartum preeclampsia 2 days after my daughter was born, and while my blood pressure is somewhat under control with medication I have a huge fear that I am going to die or have a heart attack or stroke and my babies will be left alone and have to fend for themselves. My husband works very long days and travels frequently for work and I am constantly freaking out that I am just going to drop dead from my pp preeclampsia. My babies are completely helpless, 16momths and 2 months. I told my doctor I didn’t want to be on anything I take on a daily basis, just something I can take as needed. Can I ask for more or were these 3 supposed to fix my anxiety?