Why they call your allins.
Are you only aggressive when you have big cards? Others will pick up on that, mostly back away, let you have smaller pots. But they are waiting to pounce, they've seen you make some easy money, but when they feel they "have" THE cards, they will call anything.
If its a free-roll or small stakes, players will call all-ins, to satisfy their curiosity, "did he really have the nuts?"
Your idea of only shoving with big cards is good, with experience you will know the other cards, what times, to shove. You are on the right path, building your knowledge base.