How to regain patience again

Ever since I lost my son at 21 weeks last year I've noticed I don't handle stressful situations very well and I cry at a drop of a hat. I've also noticed that i just seem so mad and angry all the time and I have low patience for my son and husband my everyday i think to myself ok, I'll be better today but I just snap over everything and then being like that makes me cry because that's not who I am or was and I feel horrible:( has anyone else gone though this? Any advice would be appreciated!