If I'm stuck in this I'm totally screwed! :P

I am doing everything the Tutorial ask, getting everything ready, but right before the attack, a month or so, the 90% of the city evacuates! :P

What am I doing wrong here!?

As said, a savegame would help. Otherwise could you say what the food and job situation is?
Other than food or jobs, being in debt can lose you a City but I don't think that would come up in a Tutorial.

I kept reloading and eventually it didn't happen. I'm sure it was just my overlooking something.

I'll give the answer to Unkalibriert just because he chimed in first.

But but-- I was second! LOL. I forget to mark that on my questions which is unfair to those who solve them. I wonder if it is too late.

That actually did bother me that I couldn't give you have points but I didn't design this stupid thing. :P

As a serial abuser of not giving credit where it is due, I'm just getting my own back. LOL. But you used the correct rule. First come first serve.
I suspect you had an employment problem. If you want some hints on how to deal with it, I've put a trick below











A way to deal with high employment:
If you notice your employment going over 5- 10% you will begin to loose happiness points. This happens if you build a housing block but employment will take longer to create. Put militia into the field and let them stand until sent home because new jobs are available.
Also, the militia will be useful against water monsters like the Kraken. These water monsters are looking to destroy shipping and piers. But they don't like rocks thrown at them, so they do a lot less damage if you have the militia near your piers. Land-based monster are nearly unstoppable and only gods attack gods.

(Edit for spelling )