Sounds like you’re on the right track, but I’m wondering if you’re dealing with some PTSD from being robbed. Certainly there’s nothing wrong with being situationally aware or armed, but be low key about it. Be a sheep dog. Blend in with the sheep (everyday people with no plan or ability to protect themselves) and just be cool. Not sure how it is at your gas station, but many gas stations I delivered fuel to had strict policies against employees carrying any kind of weapon. With that in mind, you don’t want to get busted packing heat. But for Pete’s sake, if you’re going to keep a gun, keep it on your person and not under a counter or in a bag. On your person is the safest and most useful place you can keep it.
If you can park your car in a more well lit area, that might be beneficial. It would probably be a good idea to carry a good OC spray. You’re probably more likely to need a non lethal than your gun while working at a gas station.
If you have the ability, take some shooting classes. Not classroom classes. Shooting classes. Classes which emphasize holster draws and movement. Your gun and permit are worthless unless your skills are developed and recently practiced. Skills are perishable.
Sounds like you’re on the right path. Hope this helps, but if possible seek professional training from professionals who continually get top tier training. Regularly. Random opinions/ advice from people on the internet can be a mixed bag to say the least. (Including mine. I make no claims about being any kind of expert.)