Difficulty of the Titans Campaign

So I just picked up the game for the first time since I was a kid and have been really enjoying playing through the campaign. I play a decent amount of strategy games so I've been on titan and I have usually been able to get through most missions in at most 2 tries. I'm now on the first of the Atlantian missions and I honestly don't feel like it's possible. I'm getting slammed with huge armies, there's no resources nearby, I just don't see what I'm supposed to do. So far my best attempt has been building tons of towers in my little starting base and retreating to them each time there's a raid to try to actually build up an army. I managed to get every upgrade and pop-capped an army, then moved out to try to find the temple and got wiped out by three armies of norse. Is this normal? What is going on here?