Is my teacher being unreasonable or am i wrong?

I had this gym ignment due on a monday of a week. I was absent that week on monday and tuesday due to bronchitis and pneumonia. I went to school wednesday (even though i wasn't supposed to because i was still very sick), but i went only to do some tests and stuff and then i left. I went to school thursday because i had to do more test and i had to remake some up at lunch and went to remediation at the recesses, leaving me no time for anything. There was no school that friday. I went to school the monday after and spoke to my gym teacher asking if i could give it in tuesday because i forgot about it completely (i was crammed with a lot of homework) and she told me yes. I came the next day and she told me that i can't give it in and she won't accept it nor does she believe that she said i could give it in that day (and i promise you she said i could). This ignment is worth a third of my term. I have always changed for gym, participated in gym, and have been polite with the teacher. I didn't have time the first week and i forgot the second, but she told me i could give it in. Am i being unreasonable or is she.