IDG Answers is a community of experts who are passionate about technology. Ask a question or answer one below.
answer to your question is YES.
it is possible for someone to hack into your system and control your webcam. Most recent example that i've heard of is with FBI Ransomwares. There are several variants of it and some of them have been reported to be able to hibernate in poor unsuspecting virtuous individuals computer and control webcam too.
note : what i am not sure about is if they can control a small LED bulb like thing that you might have seen right next to your webcam that lights up when webcam is in use.
Maybe worried is too strong of a word, but it can happen, and you should be aware of it. The same security measures you take to prevent any trojan from being installed should go a long way towards keeping your webcam in your control. You can always use a piece of tape to cover it if you are really concerned.