Pregnant with a toddler and stressed beyond belief

I'm 11 weeks pregnant with a 16 month old and I'm beyond stressed. I'm a SAHM and my LO has been behaving very, very badly. I get so mad and stressed and I end up yelling and she just screams and cries and throws stuff at me and I don't know what to do. I'm so stressed that it makes me sick and my body hurts. I try to have patience with my LO but it's so hard because she is still nursing and I don't want to nurse anymore, I hate it. I don't know what to do but I'm worried about all the stress that's being put onto the baby. And I wish there was a way for me to control my stress/anger when my LO is behaving bad but it's so hard.