iPhone acting weird and may be hacked

Can anybody help me with this?! So, about a month ago, my phone’s been acting weird. I’ll be using an app and it would close the app all of a sudden and another app would open. I would use Safari and when I try to scroll up or down, it would zoom in or out as I’m trying to scroll the page. My phone isn’t charging, I would have to plug and unplug it a few times for it to connect. At first I thought it may be the charger, but I’ve let others use my charger and it works fine with their phone. I’ll be texting someone from the front view page and it would close all of a sudden. And a few other thing so can’t exactly remember. The main reason why I THINK my phone is hacked is because a few weeks after that had started, someone had used my card to order some McDonald’s in Florida, while I’m in Minnesota. I called my bank and they told me it was a mobile order, which I had deleted my McDonald’s mobile app since I don’t use it. I had my bank card in my phone to use the Apple Pay so I’m thinking that’s how they used my card. I’m not sure if these two things are exactly connected, but my bank did say that they have seen this happen before and my phone may be hacked. Does anyone know how I would know for sure if it is or not? I also did a factory reset (lost almost everything I had in my phone) and my phone is still acting weird from time to time.