I feel like I'm being bullied by my boss, what should I do?

I've been working for a company for about 6 or 7 months now. When I first started, things were great. I got along well with my boss and co workers. Well, eventually, some people started picking on me, my boss included, about a blond moment that I had. I was okay with it. I mean, it was definitely not one of my most intelligent moments. After a while though, my boss started picking on me more. He put steaksauce in my drink while I wasn't looking. He'd call me ditzy or a dumb blond in front of my co workers. It bothered me, but I'd always just laugh along so I wouldn't look like a "Debbie Downer". Then, I got into a disagreement with his bestfriend, who is an employee just like me, and all of a sudden I started losing shifts. I heard that my boss's friend may be writing the schedules for him, so I got pretty upset. Things at work started getting pretty frustrating for me, especially now since, fun and joking aside, my money (shifts) were being taken from me. One night I was standing at a computer printing out a guests check, and he sprayed computer Duster into my ear so close that I believe he slightly perforated my eardrum, because it was sore for 3 days afterward. I think that he heard about how upset I was, and I even threatened to tell our corporate managers because I don't have medical insurance and couldn't afford to see a doctor. My boss started critiquing everything I did. I do my job well. I'm on time, I work even when the restaurant isn't busy. I clean and detail things, without being asked. I have open availability, I don't request off. I've worked every single Sunday since I've started, even though I was promised that Sunday shifts were rotated (My churches services are one of a kind and only available during evenings, when I'm scheduled) , but I don't complain about it, because I'm afraid it will effect my other shifts. He recently changed my schedule to only 3 nights a week. He took away my Friday and Saturday night, which are the most busy nights of the week. I'm the only person he has done this to for over 3 weeks in a row now. I've been trying to pick up shifts for other employees, which was working out for me for a while, until one Saturday when I was on call, he told me he didn't need me. Well, another employee offered me his shift, and I called to ask if it was okay for me to work for that employee, and he shouted at me and told me that he didn't need me, and I wasn't allowed to work, then hung up on me. He then, called me back 10 minutes later threatening my job because he said "I think I'm running some kind of show". It's absolutely ridiculous. The last shift I worked with him. My guests bill needed some attention, and he completely ignored me...like I wasn't standing there for over 5 minutes. (which is a long time in the middle of a dinner rush) Another employee asked for help and he walked right over to him and helped him out, and then turned around and continued to ignore me. I'm so tired of him, but I really like my other boss. When Nathan (bully boss) isn't around, I have a great time working there. I love the company, and would love to continue working for them while I finish school. There are a lot of things that I've left out, just because this is already the longest question ever. I've asked for a sit down talk with both of my boss's together for this Friday. I'd really love to express my feelings, but I'm afraid that this is going to blow up in my face. I just can't take being treated this way anymore. I don't feel I've done anything to deserve this kind of treatment.