Stress and miscarriage ?

So I had a miscarriage last year due to stress. The stress caused white blood cells to produce and that caused an infection and made me miscarry. I recently just found I was pregnant and me and my SO are fighting some days and I'm scared to have another miscarriage. I guess my question is how much stress would I have to undergo to miscarry? I don't really remember how much me and my so fought last year to cause it but I'm scared the fighting we've done will cause another one? Please help ! I'm scared