Issues at work

J
Update: my boss decided when I arrived this morning to write me up AGAIN because I didn't stay 40 minutes later yesterday, and instead planned on making up my missed minutes from yesterday a little bit each day.. As he has told me and my coworkers was accepted. He even did this one in front of HR who basically laughed at me when I said I felt that he's singling me out since becoming pregnant! WTH?!? 😡 
Anyone else having issues with work? Today my boss wrote me up for being late due to an appointment because he "didn't know about it", but I have the email conversation where I told him when the appointment was, and his confirmation that it'd be okay. So now I have to dispute it with HR because he has no record of that email or conversation. He also got mad at me and told me I need to take less bathroom breaks... Between all the water I drink to stay hydrated since its in the 90s and I have to wear long pants and long sleeves, and baby sitting just right in there, I just have to pee! I'm starting to feel like this pattern is just going to continue on. The office has been silent all day, even other employees because they feel the tension. Am I alone in having issues with work and my boss? Any advice on what I can do without causing more issues?