Re: My period is late and I'm on the pill????
I think it's absolutely the stress from your tonsillectomy causing your problem. I had that done about 2 years ago and I was about a week or more late for my next period after the surgery. Reason being, when you have surgery, especially something as majorly stressful as a tonsillectomy (I will NEVER forget how much pain I had afterwards!!), your entire body is affected. That's the kind of stress that will absolutely either delay or make you skip your period all together.
Also, when you are on the pill, it's possible to skip your period anytime for no reason at all. There were about 3 times in the years I was on the pill that I ended up skipping a period for no reason. It's something like 99% effective against pregnancy, so I don't think you should worry so much. I'm assuming that you're in enough pain after your surgery that you probably haven't had sex since your surgery. And I'm also assuming that you had a blood test before your surgery for pregnancy, because that's very standard before any surgery to get that done to ensure you're not pregnant before getting anesthesia. If you haven't had sex since the surgery and it's only been 2 weeks, I highly, highly doubt you're pregnant.