Financial advice please.

I lost my wife to Bowel cancer 16 months ago. We have 2 small children who were aged 5 and 3 at the time. We had Life Insurance in place ( I took it out thinking it would benefit Laura if I were to pass away given I have lost my dad and sister to cancer - I never, ever thought I would lose Laura first).
The insurance company paid out the lump sum (tax free) which I then invested in various places with the help of an advisor for short term and also longer term for our boys. 
Laura and myself both worked full time but since her passing I have had to drop down to part time hrs and reduced number of days to look after the boys.
I wanted to check something regarding finances if anyone can help please? 
My new hours mean I am below the higher rate tax bracket and I am able to claim child benefit (I was able to claim bereavement support but that is now coming to an end after 18months).
However I now understand that because I receive interest on my savings I have put away I am now going to go into the higher tax bracket which means I now have the child benefit wiped out (the higher rate means you lose it) (or not claim the payments), I now pay tax on the interest I receive from the tax free life assurance which then contributes to my PFA. It seems the gov get you either way for tax.. 
I'm losing the bereavement support, I can no longer claim child benefit and I have to pay tax on my savings (the life policy payout) all because I want to put money aside for our sons future and I want to save if anything were to happen to me). because it takes me above 50K a year.. all this on top of a reduced salary and hours. I do appreciate 50k is a lot of money but when mortgage rates are what they are along with the cost of living.. you lose a partner and their salary, you have two small boys to raise alone and the gov think 18 months is long enough for you to receive financial help and then take your child benefit from you and tax your savings on top... just all seems a little unfair to me? 
Does anyone else find you seem to get penalised by tax as soon as you think you are getting straight.?
Thanks