Pregnant too soon after MC?

I had a missed miscarriage at 17 weeks, when the baby had died at 13 weeks. I had a d&c in May and we were planning on waiting 3 cycles before we tried to conceive again. 
I've had one period so far, in June. I should be getting my next period in a few days but have been have some pregnancy-like symptoms. First I had some blood in my cm for a few days, then I was nauseous, and now I'm getting headaches and my cm is thick and white like it was when I was pregnant. 
If I am pregnant I have no idea how it happened, we were using condoms and didn't have sex when I was ovulating. I'm just afraid it could be too soon and my body won't be ready. I'm so afraid of losing another baby. 
Any thoughts?
This is my baby that I lost 💕 I miss him or her every day.