Depression, anxiety, anger

I have been depressed on and off since I was a child. I've developed anxiety and my anger has been escalated the older I get. I take it out on my fiance . He does push my buttons but it gives me not right..I feel like a horrible person who doesn't deserve to be happy . We have a 5 month old and I just feel like I broke my family up for not getting help and ignoring all these emotions and then lashing out. I feel really alone.