getting worse, quickly

hello,

i have been having a hard time mentally recently. lack of good sleep and a lot of anxiety. i think that this reflects in my playing. i have tried to look at what i am doing but i make major mistakes. my tactics are now averaging around the 1400 mark, though dropped today. my playing on 10 minutes has dropped from 1100 to 999. not today but over the past few days. 

i am still struggling with the thinking process and trying to see what my opponent is trying to do. i find this quite hard. i dont know why. i look at my analysis but it doesnt help, i am not sure where i go wrong. i see that there were better options but i dont see those options when i am playing. people say things like "try not to blunder" which i think is harder said than done. i dont like the drop in rating as it affects my enthusiasm. no one likes to loose. 

i was thinking about getting the back to basics book by dan heisman but not sure if that would even help as this site has a tactics trainer. anyone read this book, does it help with the thought process?

thanks

simon