What Causes Short Term Memory Loss?

Over the course of a week, there has been three incidents where I couldn t remember small pieces of information. In the first, I had taken a water bottle out of the fridge and drank some of it but within thirty minutes I couldn t remember if it was mine. Another incident occurred where I had taken my charger out of the outlet and placed it on my bed but within five minutes I couldn t remember where it was, and spent a good 15 mins looking for it before finding it... not because I remembered where it was but because I look in enough spots for it. And then finally, just today about thirty minutes after getting home, I was going to feed my dog but then couldn t remember if I had already since getting home thirty minutes ago. My concern is that I feel these incidents may be connected and apart of a medical issue but at the same time, I feel like it s too early to tell for sure. Should I contact a doctor or wait to see if the problems become more frequent?