Really sorry that you are here but you have definitely come to the right place and will get good advice here. I am relatively new here but I will echo dburt when I say that the best thing that I have done is to stop being needy (crying, begging, pleading, rationalizing, etc.). This has made a huge difference in the dynamic between me and my W.
I have also learned to just listen to her. I don't talk much about me, I let her vent about her stress, her work, whatever. I just listen and validate.
My W also told me that I was a drag and that I had become a very negative person. This was hard for me to hear but when I reflected on it, I realized it was true. Think about what your H said and if you think you have really become negative or unhappy, that is an excellent opportunity for a major 180.
I know as you mentioned that you feel like you are under water. My therapist calls it "free fall". In any case, it sucks but you have a lot of people on this forum who know how you feel.
