How is your day usually in the Navy

It all depends on the rate that you pick as well as the duty station you are assigned to. My suggestion to you is to research the jobs (rates) and find one that you find the most interesting. Then speak to a recruiter.

I don't have this experience myself but based on research here is what I found:

"I served in the US Navy as a Corpsman between 2010 and 2015. General lifestyle as a Navy Corpsman depends on what you will be doing, and where you are assigned. Going further with the “where you are assigned” piece, if you are or want to be an FMF Corpsman, life is also different. FMF stands for Fleet Marine Force. An FMF Corpsman is assigned to US Marine Corps units and provides medical support to them, up to and including combat deployments. If you are an FMF Corpsman, you are referred to as “Green Side,” whereas a Corpsman stationed with traditional Navy shore units and on ships is referred to as “Blue Side.”

I was a Blue Side Corpsman. I spent my time at Walter Reed National Military Medical Center in Bethesda, MD. From there, I was assigned to Naval Health Clinic Hawaii. While I cannot comment on the lifestyle and standard day-to-day of an FMF Corpsman, I can help with Blue Side questions. A day in the life of a blue side corpsman is very similar to regular employment in a civilian hospital. Of course there are some differences with the addition of military medicine and the military lifestyle, the work is standard."

source: https://www.quora.com/How-is-the-life-of-a-Navy-Corpsman