Is becoming a nurse a draining job? If so how do you avoid that?

It definitely can be. But the rewards usually balance things out.
Make sure to remember to take care of yourself as well as you do your patients...
If your employer offers 2-4 weeks vacation-USE IT.
If you feel over stressed, it's ok to take a mental health day. You're no good to your patients if you are exhausted.
I read books, go to the movies...truly the best activity is hanging out with my coworkers after a hard day!
When I worked on the Med-Surg floor at the hospital, we knew someone was having a bad day when we would walk by each other and just nod our heads. That meant, "we're getting together at the usual spot after work", to decompress!
You will definitely have days that include tears. Let them flow.
Our job is not easy. But it is absolutely worth it.
Oh, and buy good shoes. Wear support hose. Really. 😜