I do plan on seeking professional help for this. But I do want to know if other people feel this way...

I'm a 29 year old male. Married. I have two baby girls aged 1 year and 6 months and the other is 3 months old. 

I graduated college back in 2015 and have a pretty stable job.  My wife is pretty stable as well and we have a home. Our savings are good as well. But I don't understand why I feel like my life is held together by tape and gum. I always feel like something will go wrong in my life. I always feel like this major catastrophe can happen at any moment and when it does, I will not be able to handle it. The catastrophe in question is nothing specific but it feels like it looms over me. And this has become more severe after having children and more responsibilities because I love them so much and always want the best for them but feel like I may fail them. 

Sometimes I find it hard to catch my breath. Like I'll do simple tasks around the house and realize that I need to take really deep breaths and hold at a complete inhale. I also have a hard time sleeping at night. Like a very hard time. Sometimes on REM sleep I just get a sudden burst of "Holy crap. One day you're going to die. Or the worst can happen to you or your family. Etc"

These things become very crippling and it makes it very hard to do things in my day to day. I used to have so much drive. Now I feel so void. Like I'm just struggling to hang onto myself. 

The true moments of happiness I feel are when my kids are having a blast doing such simple things. Like stacking blocks or stuff that adults find remedial.  It makes me so happy to see that they can get so much joy out of simple things. And their fat chubby-cheeked smiles light up my day...

But I don't want to just be happy vicariously living through my children. I want to be happy on my own terms. And I need help getting there....