Have I been stimming and does this mean something?

For as long as I can remember I had like four main things when I got like happy i guess, my whole body would shake, originally would quickly bat a pencil or something on a flat surface, or I would clench up my hands or tightly rub them together, and I would like put my nail under my fingernail too. I never thought anything of it when I got older cuz it kinda stopped for a while when I wasnt taking care of myself properly but it came back really bad recently, I learnt about this thing called stimming? Is that what it is? What causes it? I don't think its normal because a lot of adults would comment on it and my parents made fun of me for it.