Brown spotting

Victoria • TTC #2 for 16 months. 3 Medicated cycles that failed. 1st IVF worked!!! And I have 3 frozen embryos.
This morning when I got up there was a little brown blood or brown colored mucus in my underwear. When I wiped there was just a little and it was lighter. Gotten less and lighter today. 
Most everything says it's no biggie but I'm still scared.
I'm 15.3 weeks now and all of my ultrasounds and even my blood tests for chromosome issues were all perfect. 
This is my 2nd but had to do <a href="https://glowing.com/glow-fertility-program">IVF</a>. Haven't had any spotting before and don't remember  this happening with my daughter. Haven't called my doc because nothing I have found says I really need to. It's either okay or I'll miscarry and there is nothing I can do?