Not sure where to even begin

Hello. My name is Tabby. I am 26 and a mother to 2 kids ages 4 and 1. I also work full time. I have been battling severe depression and anxiety for years but have never seeked help. My mom used to tell me it was all in my head and I needed to just stop so I just began keeping it all in. Since then, I have never let anyone in until my husband. Now with kids, I just want to be better so I can fully enjoy them. I've been dealing with constantly feeling lonely even when people are with me, my marriage has been extremely up and down since the beginning, I am always tired and have suicidal thoughts because I believe no one would even notice until I didn't show up for work. I have a lot of fear of letting others in because they all leave eventually anyways. I have no real close friends and the only person I talk to is my husband and he never really tries to understand. I feel disconnected from the world and I truly have so sense of self. I have no interests and no hobbies. Nothing ever seems fun to me even when I try to find something. I am tired of being angry or annoyed and rarely happy. Most of the time, I feel as is my kids would be better with a new family.