Need advise!!!

Janice • I`m 29, husband is 31. I have pcos and a bicornuate uterus. This is year 3 ttc. MC in y1 Baby #3 is now 16w 2d`s
I had a BFP on Friday completely unexpected, due to 3 years trying. Two years ago I had a mc at 6 weeks. I had a faint line when I tested that time. This time I had a very dark positive line. Nurse thinks I'm around 6 weeks now. I'm just scared as what are the chances of another miscarriage??