yeah that's the way i felt, i blasted through all the campaigns in professional mode and i have to say the fear of running out of ammo was always there. not to mention the HP bar might as well be a decoration. almost everything 1 shots you or at the weakest halves your life. fun times.
Professional mode is not hard at all, it is nothing compared to 5 where u can die in one hit. You can survive 3 full hits with full health at least (unlike 5 where you can die in one hit with full health).
With so much mobility in this game, it is EASY to avoid damage (running, sliding, rolling, counterattacks, quick shots and more).
If u need to rely on unlimited ammo, then u are not using all the mobility of the game to take out the zombies and other enemies. Only Chris's campaign should be the only one where ammo can be problematic.
As for skills, defense up is great to reduce damage for all the campaigns. Breakout is great for Leon campaign while Firearm is best for the other two.
Last third skill Field Medic is great if u are playing solo, if it is co-op it can be be Item Drop if u run out of ammo or want more item drops.
I've been watching my friend stream professional mode with a friend on their first playthrough blind run and they dont die at all (or rarely) unless it is from QTE or cheap-death events.