If you are a nightowl, awake into the night and if you WOULD sleep late if you could and find it difficult getting up then taking a high dose B12 in Methylcobalamin form might help you. It can help reset the body clock and forces the body to shut down at more normal times. The itching you mention sounds very familiar to me because I itched quite a lot and discovered that it was caused by a hyperpermeable stomach and gut. High dose B12, I take 20mg a day, also helped with this because it stimulates the activity of TH1 suppressor T-Cells which suppress IgE antibody production which cause the itching. It won't cure hyper permeability on it's own but it could give you some relief from itching and insomnia while you tackle the issues. 20mg of B12 per day has reduced my itching quite significantly, not 100% but a lot better.
With the issues you have reported it does sound like this could be your problem. I am looking to fix the same thing myself but it causes a great deal of tiredness with me, affecting my hypothalamus/pituitary gland. You might have a similar thing yourself if your sleep is affected because the hypothalamus does affect the body clock. Check your symptoms against hypothalamus/pituitary involvement to see if there is any chance that it could be an issue.