I'd say keep your CNA job. Because you are per diem, you likely have options in terms of scheduling. Maybe pick up shifts during breaks from school (including the long summer break) and focus on your other commitments while school is in session. I agree that CNA experience as a nursing student is a positive. The lines of work are different for sure, but CNA skills are actually basic nursing skills delegated by the RN to the CNA, so the future nurse will need to have mastered these skills anyway because they will be supervising the CNA staff in their future nursing role.
Some benefits of working as a CNA while en route to becoming an RN:
1. Learn the importance of teamwork. I cannot emphasize this enough. There are many instances in the health-care setting where you simply can't do something on your own and you must be able to seek out help from others and be willing to help them out too. Plus, you have to be able to collaborate with a variety of staff on the patient care team.
2. Learn how to communicate with patients. This takes practice because not all patients are alike. Like us, they all have different personalities and ways of communicating with others. Working as a CNA will expose you to lots of different patients with whom you will be speaking with. It's great practice, actually.
3. Time management and resilience. I hear a lot of people whine about clinical. Reality is that in nursing you have more than one patient, you don't get to spend hours researching them before taking them on as an assignment, and you don't always have a Momma/Dadda nurse (clinical instructor or mentor or supervisor) at your fingertips to help you figure every little problem out. While CNA work is different than RN work in many respects, both still have to provide for the needs of many different patients/residents during a given shift. You learn all about prioritizing and problem-solving real quick. Suddenly, the one patient you have in clinical doesn't seem all that stressful.
4. Improved empathy and compassion for others. The CNA works directly with the patient/resident and will be exposed to all different types of emotional and physical challenges faced by these people. We live in a self-obsessed society, and even nursing schools themselves are set up to have us compete with one another (just the nature of the beast), so I think some time, albeit stressful time, working directly with others in need helps to put things in perspective.
5. Exposure. Even though a CNA is not an RN, both work together closely. You get to see what the nurses do on a day-to-day basis and you are exposed to the general medical environment. There's lots to learn here.
5. Motivation. I work as a CNA, and while there are parts of it that I love, there are those parts that I don't particularly care for. When I feel discouraged by nursing school I can just remind myself "Do I want to work as a CNA for the rest of my life?" No, I do not. This is the first semester that I have worked as a CNA. So far, I'm actually doing better in terms of getting things done, being on time, staying motivated, etc.
Whatever you decide to do, good luck!