Bad luck mate I had a similar experience last weekend a rod went off for the first time on the Sunday morning after being fishless since Saturday morning and lost it, knot went at the hook eye totally my fault it was one you tye and think that will do. I should know better as I have been a very keen angler for twenty years. So I have learnt from it and its double checking now. One tip I can give is buy a bottle of Kryston Bondage a small application then rubbed in with a cocktail stick will give you alot more confidence, but if your having problems tying then get some friendly Angler to help tye up a few basic knots its much easier than doing it from diagrams on your own.
Regards Ian