Ugh, feeling overwhelmed need some job advice please!

Don't sweat it! From what I can observe, the average CNA works about a few weeks before they leave. Just give 2 weeks notice, and that is all that is expected from any professional.

Yeah, most places schedule dynamically to make it hard to work 2 places at the same time. Its hard to work 2 full time jobs anyway. You can't be going to Pre-nursing school and wiping hineys 80 hours a week anyway

The 'professional way' to leave a job is to be honest, but not critical. Definitely give 2 weeks notice, or more, if possible. You write a simple letter that states that you are having difficulty with scheduling and that you are compelled to leave (you do this in a sentence or 2). You thank them for providing you with the employment opportunity, and that's about it.
Whether they want to provide a positive reference is up to them. If you're not aware, basically few people give poor references as they're afraid of a lawsuit. Most employers are asked if they would hire you back, and they give a simple yes or no answer. So, as long as you write a polite resignation letter, and you've been doing your job well, you should not have a problem. But yes, you don't want to make a habit of short stays on your resume. But if this is honestly an issue of being able to schedule between two agencies, that is a reasonable issue and you can honestly tell future employers that you were new to the business and didn't realize you would have this issue.
As far as working in hospital, yes, you get a whole lot of experience. But if you look at some past postings about differences between hospital and LTC, that would be good. I won't repeat postings I've made (I did hospital and LTC). There is a world of difference. If you do not like constant changes in priority, turnover of patients, constantly walking into rooms every shift with new people, you won't like hospital. There is no 'routine' that you can get in LTC. Not everyone likes that. The rest of the differences you can find on past postings.