First time with a babysitter - my kid said something that made my blood go cold

So, we vetted this sitter through some mutual connections. She had a couple nice reviews online. She works in the childcare industry when she's not nannying and she had a solid reference. She stayed with my boy a couple nights when he was asleep after bedtime and she seems very sweet and nice.Recently, I had to use her to watch the kiddo for a couple hours while I was at work. When I got home everything seemed fine and my toddler (boy, 4) didn't want her to leave. He was hoping she would stay to keep playing. Cute right?Then tonight I was on the phone with a relative and they asked what my toddler thought of our sitter. He says "we played doctor." uuuuuhh...okay. "how do you play doctor, sweetie?" and then he replies with "it's a secret." At this point I'm basically like holy-shit-law-and-order-svu level of concerned. I asked him to demonstrate how to play doctor, and he was very evasive.My toddler and I talked for a long time tonight and I am unable to get a clear answer on what exactly happened during this episode of "Doctor." My toddler still likes the babysitter and when I asked if he would be okay seeing her again he was fine with it - enthusiastic even.I said things like:"you can tell me anything" - nothing"I won't ever be mad if you tell me something is bothering you" - nothing"what was the weirdest part about playing doctor?" - to this he said that he 'snuggled' with our babysitter. Which isn't a big deal - but in this context it's making me weirded out.He basically landed on this idea (in all the sense that a 4 year old can muster) that it was weird for him to snuggle and he didn't want to tell me b/c he thought I would be angry. But he also said that next time he would snuggle because he "has to." I obviously informed him that he never "has to" touch or be touched. I told him I will never be angry if he tells me he's being hurt because I'm here to help him.I told him he can say "NO" in a loud firm voice if he ever felt like someone was touching him in a way that he didn't like. We talked about how his body is for him and not for anyone else.By the end of it he was kind of like "whatever dad, can we just play with these transformers or something?"Jesus, I hate that I have to even think about shit like this. I wish I could go back to just changing diapers and losing sleep.Am I taking crazy pills? Should I talk about this with the sitter? What is the likely-hood that a 21 year old female would do something 'icky' to a 4 year old boy? Is that even something that happens? She seemed like such a sweet girl and she was so nice with my kid. Any one get a weird feeling like this? Am I just being a freak because I watch too many crime dramas? via /r/Parenting http://ift.tt/2n3p7U7