Question: My probationary period passed three days ago, I have not been told if I passed it, and I have my evaluation early next week. Should I assume that I have passed probation?

Answer: 
No you should not assume that you have passed probation. You will likely be informed of the results of your probationary period during your evaluation.
You should wait until any official confirmation.

I had a similar situation 4 months back, the confirmation meeting was delayed because of too much work.
Since you know your meeting is next week, you should wait until then.
In the meantime, you can take feedback from other colleagues about your performance to ease the pressure.