Firstly, we would not recommend Agnus castus; your cycle is already long and Agnus castus will most likely make it longer.
Secondly, we would urge that you get your stress levels under control before you try to conceive as high stress levels can prevent conception and also, unfortunately, can be a predictor to miscarriage.
Eleutherococcus can be helpful for your stress levels as well as as much rest and relaxation that you can manage (not easy to switch off with house to run, but try).
You may also wish to look at using an iron supplement to give you a boost.
Hopefully, by getting your stress under control everything else will fall in to place.