This can actually be a tricky answer. If an employer wishes to terminate your employment agreement then most states would agree that he would have to inform you...BUT there is nothing requiring him to pass this information in a manner convenient to you (ie phone, text, e-mail, or regular postage). If he chooses, he could opt (at his discretion) to inform you of your termination in person. In your background information you mention texting him, did you ever actually go in to see him in person? If you didn't then there may be nothing you can do because he'll simply state that he intended to discharge you but you never came in for him to do so. Additionally, in order for a lawsuit against him to be successful, you would have to show that you exhausted all reasonable means at your disposal to resolve the issue. Again, if you didn't go to see him in person, then you have not met this standard. Furthermore, if you live in an at will state (such as Washington) then you have even less juice because even if you were to consider your agreement to work around your drama schedule to be a binding contract it would be superseded by the law which would allow him to terminate your employment without giving you a reason.
At this stage, your best bet is to forget about him an move on, but I'll leave you with this: An employer will always put their needs ahead of your own regardless of what casual agreements you may make. Personally, I've met literally hundreds of employers (including two who I've worked for) who tell potential (and current) employees that they will work around school schedules. To date, not one of them has.
Employment Counselor for Washington ESD.