I know how you feel, I'm in the same position and it isn't nice.
Just one word of warning. Magnesium Taurate is the best form to take, as you will see if you visit the website mentioned earlier on. Make sure you also read the section on Candida. I see you think you may have it. Mg will make it worse. See if you can't get tested for Candida. The gut fermentation test is quick and easy and quite cheap..at least it is in the UK. You can also be tested for Mg deficiency which is also fairly cheap.
Don't bother with other cheaper forms of Mg, they are not the same. Many of the cheaper or broad spectrum multi-vits have Magnesium Oxide or Carbonate. Very poorly absorbed. While other forms make Depression worse.
If taking oral supplements make you stomach bad then you can try injections. I'm self administering at the moment..hurt a little but got to be worth a shot (excuse the pun!!)