No method of contraceptive is ever 100% effective, so it is still possible to get pregnant if your tubes are tied.  If you are a fast healer with cuts etc, then the chances of you getting pregnant even with your tubes tied are higher.

I want to get mine done as I think 5 babies in 6 years is more than enough and also because I don't think my body will cope with any more pregnancies.

yes my best friend fellpregnant while she had her tubes tied one of the clip came off

Yes it is possible. I would get a pregnancy test and then see the doc.

sadly yes. some times the op isnt a sucess, same with a vasectomy.

A friend of mine had hers done and fell pregnant a year later.

If you are worried see your gp