Try liquid iron, found in most health food store
Just a comment, as a doctor, Iron is the most common cause of supplement danger - many deaths. Constipation is a common side effect, but if you take too much, it WILL KILL YOU. The only reason for extra iron is for gross dietary insufficiency (think vegan that doesn't eat leafy greens, etc.), or most commonly, BLEEDING.
BLEEDING can be menses/periods if excessive, ulcers, hemorrhoids, or even cancer.
Don't mess with it! You could mask the problem and regret it.
My suggestion, as others have said here:
1. Reduce stress (all of us need this!)
2. Supplement what you are lacking - most of us NEED Vit D supplement, I and my family take (and I recommend) 2000-4000 IU per day, liquid Vit D if possible. It is very cheap, and no side effects.
3. Sleep is crucial, especially deep, non-REM or delta sleep. Ah, the good old days of childhood.
4. Adequate diet - big deal here, and varies for individual. Adequate protein for breakfast instead of carbed up cereals, less bread period during day, and more frequent split meals throughout day is the best in general. Avoid dairy or gluten products if you have sensitivities, but don't go over-board for the hype nowadays.
Message me if you would like most GENERAL suggestions.
Thyroid conditions are also common, and can be easily treated. Naturopaths are the best to consult, then a more holistic MD. Many chiropractors have additional nutritional qualifications. Don't trust Auntie Joan or a brother-in-law with MLM berry juice or expensive vitamins you don't need from an expensive vitamin store. Diet and whole food sources are ALWAYS the best. And don't let a salesman in a store that profits off you do the recommending.