Horrible case of tangled hair. To use.

Hello, My hair is severely matted and tangled. By tangled I do not mean knots at different lengths of the hair. In fact it seems like chunks of my hair are twisted to form this huge ball of knot that has my every hair possible. I have tried everything, using fingers from the bottom, hair oil, serum, conditioner, but nothing works. The knot is so severe and big that the hair products are unable to penetrate all the way into the centre. Please help. I do not want to cut off my hair which seems like the last resort (Looks like I may have to shave off my head) To those wondering, I am going through a phase of depression after delivery and trying my best to come out but i do not know how this happened. My hair was uncombed n matted so I tried using conditioner to detangle my hair n I thought I did, but this huge knot has led to another hit in my depression. Please advise any strong detangling product to use.