Hi Jenarry, I think you really need to look at your life,you need to be strong and find the courage to speak about your feeling to your current partner.
Going through the motions is no way to live life.
Your ex has damaged your confidence in a big way and on top of your sons diabetes you have had a lot to deal with emotionally.
It can be easy to get involved in another relationship as a coping mechanism,someone new showing care and attention is a tonic for anyone,but you need to be honest with yourself and your current partner about your feelings as staying together plodding on is no good for either of you.
My thoughts and good wishes are with you Jenarry, life is too short to live settling for second best.
I would suggest as others have counselling may help because you are grieving for the loss of the relationship and your sons health,I have found in the past St Johns Wort to be a mood lifter, I know some people are sceptical but it's definitely worth trying.
As for the job,again like others have said these days jobs are hard to find but if you have the opportunity for change go for it, if not like many think well without my job would my life be worse without the income? hopefully this can put a different perspective on things regarding the job.
Good Luck Jenarry and keep us informed x