Ive been battling back and forth in Umbras Veil and trying to complete the battle with the undead in the fairy shrine but used all my gold to heal when i was super close to unlocking the third pet party slot. I dont know what to do to get more gold.

Try sending some of your pets on missions, using the town to heal is a money sink and not viable to keeping your gold
you can make a decent amount of gold from sending your pets out on missions from the barracks and the rewards are often a mix of potions, elixirs, and more gold.

Thank you, i forgot about the missions!

Of course! We've all been there, so it's easy to gloss over things like this. XD

you can sell old gear you don't need or want

One other thing. Do not, I repeat, do NOT pay the healers to heal or revive your pets from this point on. It isnt actually necessary to do so, unless youre in a hurry to get through the game storyline. If you just leave your pets alone for awhile, theyll heal & revive on their own in a couple of hours or so.

Playing the seasonal festival helps too, like even if you can't get into umbra's veil yet, then just doing the other tasks such as trick or treating [for the fall festival], gives you the daily tasks that gives you chocolate coins, which you can in-turn sell in the trade broker for some good gold - and you get those things for free daily from the tasks ^^