I do not think you're stupid . . . every pregnant woman worries about her baby during pregnancy! After all, women already love their babies before they're even born. You obviously know what things are not recommended during pregnancy (like lifting heavy objects), so I won't repeat that advice. I understand that at times you might feel you need to do things yourself that you know may not be wise. However, as your pregnancy goes on and physical tasks become more and more difficult to do, unless it is an emergency situation it's not worth taking the risk of hurting the baby or yourself. Leave the task undone until someone you know can do it for you.
The piece of mind you'll have is more important than completing the task and then worrying about whether you harmed the baby. You're correct: If you've had no cramping or bleeding, and you continue to feel the baby moving, most likely all is well. On the other hand, if ever you're worried about your baby you should feel no guilt about checking in with your health care provider to assure that all is well.