When I was in secondary school, once I had three exams in one day, english listening test, english writing test and history test. On the exam schedule, the first exam was 40 minutes. A ten-minute break later, the second exam was 70 minutes. The third exam was 2 hours in the afternoon. Because the first exam was english listening test, I assumed that the second one was english writing. However, when they passed down the paper for the second exam, it was on history. I was completely shocked and I did not do well.
Well it happens sometimes. But you should take care of these things. Anyhow, it was in past so you should forget this mistake and stay focused on your present and future. All the best .
That is a tough exam schedule. Sometimes its better to ask than to assume. But I know this situation taught you for future situations. All the best :>