Samsung Galaxy S3 — Know if someone used my phone?

Hello,

I would like to know if there's a way to know if someone used my phone at a specific time when I wasn't using it.

I have a Samsung with Kitkat 4.4.4
It's not an S3 but I thought it's the closer version to it, the version I have is not listed in these forums, it's a Galaxy Grand Neo Plus

I would love to know if there's a way to find out what they've accessed.

I found that in some android phones you can put the code * # * # 4636 # * # *
and that will give you a list of the last apps that were used and their time.

My Samsung don't have that, I heard I can make it work if I root my device, will that help?

I need something please help me experts! This will mean the world to me. I have depression and it can't stop because I'm so worried for 4 days now.
This is a learning experience for me, so next time I will be more careful.

But I just want to know if my device was used last Tuesday morning. That's all. I won't even care about the details.

I will be so grateful if you help me out.