try this: U- = you & -amka = wake up & -je = "how". maybe that helps to remeber
What is the "me" after the U mean then?
It marks the past participle.
https://2seedsswahili.wordpress.com/2013/05/16/swahili-unit-3/
This is hard to remember
Why is it wrong to put Wewe first? Wewe umeamkaje
It's not wrong, it's just a matter of emphasis. In other sentences they have used it and other emphasising pronouns like 'mimi' . They need more flexibility in the answers rather than marking variations wrong.