For a long while, and still on some days, I wind down in the evening by drinking some herbal tea; chamomile and valerian are both excellent.
I did a 3 month course of a supplement that had 5-htp, L-theanine and Taurine, also over this time I took a Chinese supplement with a lot of I don't know what (this was recommended by an awesome D.O. that I see regularly). I've read some things about 5-htp being a bit risky for persons with heart valve matters, and use in/for the long term may not be good on/for the heart valves. I suggest googling that if curious.
When I began that 3 month course, I also cut out a lot of foods I'd been eating regularly most of my life; dairy (which now over 6 months later, I consume in minimal-moderate amounts, as meat I also now eat in minimal-moderate amounts -prior I eat both in large amounts basically every day-), and I went more or less 'towards' the gluten-free approach (that is to say, I cut out a lot of flours and in avoiding cheaper foods like chips, going for the ones and things that are with less or better refined sugars and salts), I prepare and cook most of everything that I eat and try hard to eat Organic (dairy/eggs/meat) which is to avoid the antibiotics plus hormone as well as avoiding GMO foods as much as possible, I realized that -I may be 'sensitive' to gluten and am definitely 'very sensitive' to many sorts of sugars-, also I do around once a month visits to the D.O. who does both Acupuncture and Cupping (google it if you are unfamiliar, it's a bit intimidating but relieving for my neck and headaches -I have many typical, but more often than any one I know, other health matters mostly ENT/headache/neck arthritis-...), I do daily stretching that is sort of meditation-like.
With all that said, I can not point to the 5-htp alone, yet all of the above (which some of related to the cooking, organic and stretching I've done for a couple of years now) definitely resulted in some beneficial changes; however, I still deal with Narcolepsy and Cataplexy most every single day.
I do not take any meds because as like you'd said for you, for me also, the side effects definitely did not outweigh the benefit (in fact none have brought me any benefit).
I'm not saying at all to, nor to not, try 5-htp.
For me, something within the combination of it all above, changed things in ways but in some odd ways; I definitely feel generally a bit better (a few less headaches and inflammation like aches/pains) and with slightly more energy but for instance my Cataplexy had become more intrusive in simple chit chatting (example, being asked directions on the street, as I'd respond Cataplexy intrudes and makes me appear that I'm on crack or heroin) but at the same time it had slightly allowed me to have more strength for longer during physical activity (skateboarding) before Cataplexy intruded. At this point though, around 4 to 5 months after finishing the 3 month course, I don't plan to take such again.
The biggest thing that works for me, and this is near impossible in the manner of living perhaps especially today, is avoiding stress. I too, deal with the mood swings, anxiety and also depression. In my own mind I'm not necessarily at all sad, but perhaps frustrated and often likely 'unpleasant' to be around but I can't help think that's due and/or attributed to the difficulties of many sporadic health matters and then the big N w/ C which is so often just entirely misunderstood and pigeon-holed immediately by others. Socializing is so difficult, to engage with others doesn't happen unless they engage with me first or perhaps if there is some commonality/thing (like skateboarding) to draw the interest. Cataplexy is big there, because to chit chat or be joking around, jolly, I'm basically just asking to collapse...
So, maybe something there will help? Maybe not?
Either way, the best of luck.