Of course you are feeling down. You have a new baby and the people you love don’t love each other or support you. I’m concerned that you may be suffering from untreated postpartum depression as well. The first step, then, is to get an opinion from your OB-GYN.
Meanwhile, your relationship needs major work. The two of you don’t trust each other and aren’t working together to make a family. You both deserve better. Your little son for sure deserves better. Please see a couples therapist to work on your relationship with each other as well as your relationship with your family. Waiting will only let things get far worse. If you do some serious therapy work now, you have a chance to make the kind of family you all want and need.
I wish you well.