Re-entry with valid short-term study visa

[ARSemirates787]

Hello. I was hoping someone could help me.
I'm Japanese and I'm wondering about going travel around European country including Germany, Italy and Switzerland for weekend holidays. I have a valid short term study visa(till December). I'm planning the travel for three times in these 2 months, but is there any possibility to be refused to re-entry to the UK?

There are documents I can show to the immigration officer
-The letter from the university I am studying at
-Return ticket to Japan

Maybe I'm worrying too much about this because I have already proved myself in the application of the visa, but this is the first time visit to the UK and if there was big risk to travel around, I must give up the travel and there can be other problems. So would you give me your idea, please.