hi zeezeee welcome to the site, you're being proactive just by finding us so good for you!
if you have any concerns about nutrition, my signature links below may be a helpful place for you to start reading. lots of great info on many subjects here.
just going back to one thing you mentioned, there are certain magnesium supplements that have laxative action and whatever your body manages to absorb will only do you good. you could try magnesium oxide 100mg on day one, 200mg on day two, etc but once you get over 200mg make sure it's on a day you can stay near the toilet, just to be safe!
welcome again, happy reading. after you've rested your eyes that is
(ps magnesium is relaxing and can help you sleep too - for better absorption, choose magnesium glycinate. also look into magnesium-rich foods and you could think about epsom salts baths too. magnesium is only the tip of the iceberg but it's a good place to start anyway)