I have 2-3 small clusters of bubbles in my urine when I don't drink a lot of water. Is this cause for concern?

Bubbles in urine. I assume you mean when it is in the toilet and that you are not peeing bubbles? The ability of the urine to form bubbles when peeing into the toilet is a function of the concentration of protein and other stuff in the urine and in the toilet bowl and how strong you stream is and I suspect how want the water is. So if not peeing bubbles this is normal. Check when bowl last cleaned and with what.
Urine. 2-3 clusters od bubbles is not of concern If the urine is all foamy that signifies protein in the urine.