Edit: Solved! Gold account lets you have 5 and regular account 3, that explains it! :)

I had five weapon sets, wanted to make a new one but couldn't find a button for it, figured maybe I have the maximum amount of sets, so I deleted one. Now I have four weapon sets and still can't find a button to make a new one! Feels like such a ridiculous problem. I have created sets in the past but lately I've only been editing them, not creating.

Each user is only allowed 3 Weapon sets and 3 Scroll Sets.

If you have a gold account, that number jumps to 5. At some point you must have had a gold account and made the max 5. Once your GA expires, the extra 2 sets you made don't go away but you can't create any more since your only allowed 3. If you get another gold account you would be able to replace the one you deleted.

Ooooh thank you! That explains it!