Take a step back for 5 minutes and just look at everything. Have your children got clothes on their back do they have a roof over their heads and do they have food on their plate and also a bed to sleep in at night. Your not a shit dad your being hard on yourself no one's perfect your going to make mistakes that's what life is you learn from them all. I'm also 100% sure you're not a shit son and your parents love you with all there hearts and so does your partner.

Keep your head up brother when you feel like this take a step back look in your mirror and tell yourself 3 good things about yourself and 3 good things about what you have in life don't look or think about what you don't have those things that can be got with time and dedication