Calling in sick, unexcused absence?

I called in sick an hour and a half in advance for work. I've been feeling sick from my allergies all day, with a terrible migraine, bad enough where I can barely get out of bed for the bathroom. My employee handbook states under the attendance policy: "if you're going to be absent from work, notify your manager as soon as possible, but no less than one hour before your starting time". I would have called earlier, but I took multiple different medicines starting at 6 AM, and since my shift wasn't until 5 PM, I assumed I'd be better. However as they day progressed it only got worse. When I called, my manager started demanding why I hadn't called earlier, and told me this was unacceptable. I was practically crying on the phone apologizing, and he told me that he was marking it as an unexcused absence. Is he allowed to do this? Should I call HR?