At times when I was low on iodine or B vitamins, I've had the zombie one day functioning the next experience as well. There are other things that are supposed to have an effect like omega 3. Then there are other things like the "Atkin's attitude" which is reported to happen to some who reduce their carb levels enough to make their blood sugar too low. It might be possible to eat a weird enough diet that you consume too little tryptophan to make serotonin. It might make more sense to consider the full spectrum of relevant substances instead of trying this and that.

Also, not all vitamin supplement brands are equal. Some are far, far better than others. On consumerlab.com Solgar, Jarrow, Puritan's Pride, Vitamin World and Nature's Bounty were tested in lots of different reviews and have a very good track record, whereas there are a lot of other brands that, after only a few tests, showed problems with things as shocking as lead contamination and spoilage - not to mention the problem of simply not providing as much of the substances as they claimed to.

If you need supplements to stay happy, I hope you have a high-quality one.