Need help on Sevastopol Russian mission

[Todd77]

I'm playing on easy because I gave up on medium difficulty and nearly the game. Even so, I'm being totally overwhelmed by germans in this mission trying to hold the coastline. Ive taken out their two heavy Thor artillery's but Im overwhelmed and any reinforcements I bring in get instantly killed before the truck unloads them. Whats the strategy here to win this mission? What do I need to do?