Dog acting out during pregnancy??


So I am 15 weeks pregnant and the last couple weeks my dog has been acting out immensely. she is a two-year-old lab and has never had behavior problems in the past. She has been to training classes and always listens to directions and it has always been a mom and dad pleaser. So this is coming out of nowhere and I don't know how to fix it. I don't know what it is because I have been giving her attention the whole time and she's rarely ever alone. She was pulling on the leash so hard yesterday and wouldn't listen to me ( I even had her training collar on) and kept yanking me that I fell down a flight of stairs and caught myself face down on my arms... thank God I didn't fall on my stomach. And this morning she has Peed in the house twice while looking me dead in the eyes which she has never done before. She won't listen to me when ever we leave the house like when we're on our way to my parents house or just taking her outside to go to the bathroom but inside she listens but today threw me off because she just Peed in the house which she has never done before, because she is potty trained. Please help I don't know what to do and she's making this pregnancy very stressful already.