Clear blue ovulation test

I bought these expensive tests last night, but unfortunately not working which is ok because they are sending me a new one! BUT I have been having weird periods since forever! I successfully got pregnant September last year after years of trying, by sadly that ended up as an ectopic pregnancy and I had to have surgery to remove jelly bean and my right tube. Since then we have been TTC with no success. I have had many test la through docs who have said everything is fine, but was wondering who has used this testing kit before, success stories? Advice on how to use it if your AF turns up whenever she feels like it!! Would be much appreciated :)