I've also had this problem, I think its quite common in perimenopause when progesterone has been making a steady decline, anovulatory cycles produce even less and oestrogen is surging high in an attempt to boost the likelihood of a pregnancy with a waining egg supply.
I haven't had a saliva test before, it doesn't seem to be common in the UK, although my tests at London Bridge Hospital (for gut issues) all went via the Genova lab. However, in peri I think its often better to rely on symptoms rather than tests, particularly as hormones can have massive highs and lows from hour to hour.
I'm not sure of your actual symptoms but I have found progesterone cream to be very effective for throwing out some of the oestrogen but it can then cause more problems with more oestrogen then circulating in the blood-stream whilst the bowels are getting rid of it. I also had a bad reaction to DIM but do wonder if it was just working really well and I should have just had a smaller dose!
Another option for you, if the progesterone is just not working for you, and if the DIM doesn't help, is to take a high amount of oestrogen to take over your cycle, like how the pill works. I cannot take this option as I have silent migraines from the high oestrogen but I think a few women here have found this works for them, its just getting through the initial weeks until things calm down.