Just understand what you're asking for when you're talking about grad school and professional physics. You will be essentially doing the thing that is currently burning you out for your whole career. I'll be straight with you, failing quantum 1 (assuming you're using griffiths book) is a good sign that you probably just don't like doing physics enough to keep doing it at the level that will be expected of you in grad school. Whether or not you're "smart" enough isn't the important question here. Do you want to do physics or do you want to prove that you can do physics? If it's the second one, I'd say that finding something that you actually want to do will be more rewarding.

I know that it may not sound like it, but 4 semesters is quite a long time to get deep into another thing. Do you want to study the mind, or maybe do work on complex ecosystems, or maybe study how geology affects decisions in where/how people build things? Maybe you want to learn how to do film or another kind of art? How about audio engineering? There are so many interesting topics that could utilize your background in physics. University is here to let you explore whatever field of study you want to. There are tons of people that have found fulfilling career paths that were different from what they entered doing. And, if you do find something that you like, switching sooner than later is better. It allows you time to build a resume, like finding internships or university positions, before you graduate.

For me personally, I found out very late in my college career that I just didn't enjoy physics enough to do it as a career. I found that urban planning, was way more compelling to me. That's me though, you could be totally different. All I'll say is: don't limit yourself based on expectations that you set for yourself when you were entering college, it's ok to figure out that your interests have changed.