drink cocoa? (I use milk + baking powder cocoa, no sugar) it has a bit caffeine, so not ideal for before sleep
any food with magnesium (eg leafy greens) or omega 3 (eg oily fish like sardines, flaxseed, hempseed)
calcium is anti-stress too, so any other food with calcium (maybe sesame if you're allergic to dairy?)
B vitamins
hot shower or such?
journalling (ideally CBT-supported) or writing really BAD country/'emo crap' songs can help too??
(or maybe you could try RAP? hm?!)
for me, it someitmes helps to write down 'worst case scenarios' and ways to avoid them or what to do if they might happen or might be true... The Feeling Good Handbook gives you ideas how to deal with that CBT-way... oe maybe some sites online or other books on ACT or CBT too..
maybe try to imagine how in 50 years it will be irrelevant and/or you will laugh about it? (Even if it feels IMPOSSIBLE now!!)
or how in comparison to intergalactic peace it's just... err, irrelevant?
I think your thread may even help some younger/other people on this forum too...
hope things get better...