beta issues

Cate • 39 years old. 4 unsuccessful IUIs, 1 IVF cycle that ended in miscarriage and one unsuccessful FET cycle. Arthur Harry Pham - born September 5, 2018 (conceived through reciprocal IVF).
My first beta was 319 12 days after a 5 day transfer. Yesterday was my second beta, and it was only 479. That's only about a 50% increase. My doctor said not to panic, but I'm really worried. I have another test tomorrow. Anyone have any encouraging stories to make me feel better until tomorrow?