From: Sydney, Australia
it's spring of '44 and I am facing a swarm of Red armour after the rains stop.
Have you destroyed much soviet air / armour during 43?
The campaign is set up so that the Axis can get rid of about 75% of the soviet air force on the ground on the first turn. Also, if you're playing with unlimited air interdiction attacks (unlikely, because you would have won already), you can bust through the weak spots in 43 and surround the big tank armies. That causes lots of surrenders which is harder for the Soviets to recover from.
If you haven't achieved that, then you're toast. Your infantry will hold ground where they can, but the tank and shock armies with the big mech corps (equivalent to a tank division plus the full infantry complement of a rifle division) will pick holes in you, and you won't be able to base your air force forwards any more unless you want to lose your factories. Also if they've kept their IL-4s in production and have lots of Yak-9s to escort them, then the VVS can give your factories a whumping as well. Your problem won't be the red armour so much, but the fact that it's backed up with more infantry than you can produce, and you won't be able to cover all of the front with your Luftwaffe so where the Soviets can hit you with air force backup, you will lose lots of tanks.
The soviet factories are also producing about 3 - 5 times the number of tanks you are producing at this stage. Everywhere they can hit you in a big tank battle, even if the losses are even, will hurt you more than it hurts them. The soviets also probably have close to 30,000 squads in the pool at the moment, so big battles with lots of carnage will also hurt you, but only slow them down a little.
This campaign should be counted as a win for the Germans if the Soviets don't win by the end of it. If you're playing by that rule and can fall back slowly and steadily without too many losses, you have a chance. Watch for the breakthroughs in the South, once you lose Ploesti your oil supplies get short, especially if the USAAF has hit Essen and/or Hamburg a few times. It will happen but you want it to happen as late as possible.
Keep your front line troops within CAP range (7 hexes) of your big fighter units. Your FW-190s can still cause lots of damage to the VVS but not if they are out of range. As the soviet player I love nothing better than to spot a Pz Korps sitting 8 hexes from the nearest HQ with air cover, and pile the Tu-2s and Il-2/M3s onto it until there's only smoke and boots left.