Missed Period

Patricia • Reader, Runner, Writer, Wife & Mom (to 5 gorgeous babies)
Super worried and frustrated. I've been married 12 years to Derrick and we have 4 kids (lost 3 via miscarriages) and each of our children were conceived while I was using birth control: oldest; OrthoTriLo, second; DepoShot, third; NuvaRing and my baby; Mirena IUD implant. 
​Since giving birth to my youngest; I've been found to have Fibroids and a Progesterone allergy that 'allows me to conceive while using BC', on top of my Endometriosis.
​And each time we'd forgo BC, I'd conceive but miscarry. 
​That being said, I haven't used hormonal BC since giving birth to my youngest, and for the first time in nearly 2 years, my period is almost a week late. I have an OB/Gyn appt on the 22nd, but I'm stressing out. 
​It HAS been a stressful 2 weeks, lots of financial issues/new jobs, so I hoping its stressed related for it missing. But I'm worried. Tuesday morning I woke up ready to puke and the nausea stuck around until I had ye'ole Ginger Ale and Saltines...and a shot of Pepto. 
​How worrie should I be to be pregnant? 
We weren't really planning on having more children, my appointment is to progressively begin the hysterectomy route (health issues) and I can't take another miscarriage. I don't know what to do. I'm kind of panicking.