Am going to try and support you here in a small way, but the real answers that you may need in your life now, I may not have, as you battle with your POIS, diabetes and anything else that is present.
You say that you are going through a tough time and want to sleep better. You seem to be experiencing extreme anxiety and depression, for which you are / have been taking medications prescribed by doctors.
I think you had said before it is badly affecting your life with your children too. I can relate to this on some level, not having the energy or inner happiness to be the Dad you want to be all the time. You aren't alone. You also have these diabetes issues, so you need to take real care.
Firstly may I emphasise, please NEVER just come off medications, particularly those for depression. You probably know this already, as you are an experienced guy. Also, try not to mix too many different drugs or supposed complementary together at the same time. It is a shock to hear of some of the concoctions I have seen folks on other forum mentioning. I don't know how this can be monitored in a healthy manner through online support.
Let me suggest a couple of small things that you might throw in to your consideration, as a strategy to help you sleep and feel better emotionally, the main being a mental/physical approach to stress reduction.
Anxiety attacks! As you probably know, one of the main reasons for anxiety is what is termed the "Stress Response". Especially in POIS. I actually studied this on a course a decade back (general anxiety and stress) through Harvard Mind Body Medical Institute (now the Benson Henry Institute at Massachussetts General Hospital in USA ). To address and reverse this stress response and have our mind in a place where sleep is more likely, we need a "Relaxation Response" to encourage a degree of mental calm. In medical parlance, this is basically a reversal of adrenaline, noradrenaline and cortisol in the blood stream, if I remember correctly. Stops the fight/flight type normal human reaction to a stressor (such as in bad POIS). Won't clear everything, but can help a bit.
While all of this you may feel wouldn't apply with your situation, it may more than you realise, however, the relaxation response needs to be practiced regularly (even ten minutes morning and night time each day) to help you sleep. After a while, it might not need twice per day. Please note I am talking symptom reducing and better feelings here, and not a cure for anything.
An online credible medical resource I am providing here for your potential review. You can visit here for more information on (see links for Stress, Relaxation Response, Physical Activity, Nutrition, & Managing Stress) Link is
http://www.massgeneral.org/bhi/basics/Relaxation / Meditation CD's on iTunes
http://www.massgeneral.org/bhi/store/default.aspxThere are also, as you know, many relaxation CD's and tons of stuff on you tube for calming the mind a bit. You need one or two you really personally like.
Counseling?Also, as a question for you. Would some counselling (1-1) help you at this time, to deal with your depression and anxiety? It might help you to talk to someone periodically to help get the frustration out. Do you have this locally? Only a thought. You are unique, so what works and helps me, may be very different for you.
A Physical Approach.As well as general doctors, maybe someone in the holistic and wellness field can help you deal with things. It helps me, when I need extra support. Something even simple like reflexology treatment or other calming methods.
Can exercise also help you? I think I asked you this before. Exercise that you would enjoy, if done regularly, may help you a little to keep your mind off the bad feelings you experience. Exercise that I like? (For me, as an older guy, like you, is riding a bike on the open road, not a bike in a gym). I can do it well, and enjoy more of course, when out of my worst POIS state. In POIS, I don't feel much like it, but it helps with my mental state and with sleep.
Hope something here helps.
Please take good care in going TOO heavy down the prescription route. If you taking Seroxat, please also liaise with your Doctor, on trying anything new. There is a balance and you need good professional advice. Best to you.