So, my anxiety is making me worry like crazy

My son was having leg pains a couple months ago. I worried and everyone said it was growing pains and they went away so I stopped worrying. But now he said sometimes his knee gives out? I bugged him into telling me how often and he said its maybe happened twice since Christmas. So I guess twice this year. Now of course I googled and Leukemia and Bone Cancer came up. Now I'm terrified. My husband things I'm overracting because he had growing pains and my knee gives out randomly too. But I can't help but freak out. Someone please tell me this is normal. I never had growing pains so idk what they're like. Hes 8. And super active, always running and jumping. Help I'm worried :(