I uld also continue with the weight loss as well, as being over weight can contribute to not being able to get pregnant, if you can afford to I would personally reccomend going to an acupuncturist who specialises in fertility for some treatments, and also google natural fertility info , it has also got alot of things you can do to naturally increase your fertility :)
the role of dhea for fertility is to promote any good eggs left in a womans overies, and encourage them to grow to a point where they get released, there fore it also helps with reducing the amount of chromesomal problems due to egg issue, its really designed for older women who have issues with egg age and maybe low overian reserve, your problem shouldnt be that, you may have pcos, which are cysts on your overies, which can cause long periods of no periods due to not ovulating, if you dont ovulate you will not get a period