How much is too much information?

I'm in pain. I went to work today and was in a lot of pain - a lot. Clutching my rib cage by crossing my arms, my manager welcomed me back and asked how I was, I looked at him and had tears in my eyes. He asked why I came back so soon if I wasn't ready... I need to get back to my routine. So, all day long people are asking how my vacation was yet I'm in pain - I just said I was out for a medical procedure and still a bit groggy (no that green tone to my skin is not a strange tan). People are too polite to ask and I'm not going to volunteer the information. There are a few people that I work with and trust enough to talk about and it is theraputic to me to do so but still, there is a fine line of what is appropriate and what isn't. Even with family that is true. Anyhow, I'm still working on getting off this medication - 1/2 a pill twice a day. This weekend I'll knock it down to 1/2 pill per day and stop as soon as I can. My body is still healing.