Helen, you have come to the right place for support. The girls here on BB are all very understanding of all the issues and frustrations when it comes to trying to concieve........it'll make you realise you are not alone. Unexplained infertility and secondary infertility are really common. Check out some of the threads HERE all these girls are in the same long term TTC as you....I am sure you'll find it great chatting to them.

(And I hear you with the sister in law thing........I have one of those types if sister in laws too: drives me batty!)

Best of luck.....