What to do about issues at work?

My former coworker has been my boss now for about a year. She constantly makes comments about my personal health issues and in October after a friend died she berated me the day after I attended his funeral for being a half hour late to work. We open at 8:30 and I get in at 8, That day I called and said I would be late and got in at 8;35. Well, to make a long story short--another coworkers birthday is this Friday and she's taking the day off. I've been in a lawsuit for the past year for a fender bender I had 2 years ago. I just found out this afternoon that I have to give my deposition on Friday morning. We have a small office with only 4 full time people including my boss. With myself and the other girl off on Friday that would leave one coworker by herself on a very busy day. My boss may not be available to help cover the front desk area with this other coworker. I'm afraid my boss is going to give me grief tomorrow about the deposition, but she's know about this coming since before Thanksgiving. My attorney told me the deposition would probably be around the 20th of december. I'm also planning to take the day off so I don't feel rushed through deposition. I told the coworker that will be here Friday that I was planning that and she could hardly look at me. And then just keep giving me these little straight lipped smiles saying okay, uh huh. I can't stand this. I feel like everyone is going to be upset.