Trouble Waking Up With Baby?!?!

I feel like garbage! I can never seem to just get up with our baby when she cries at night. With my oldest daughter, i swear I'd leap put of bed if she sighed! This time, she could be screaming and i have no idea until I wake up at 8am and hubby is still trying to soothe her! I don't drink... I'm not on meds. I exercise. I eat well. I'm just coming out of a deep depression, but it's not helping my sleep situation. Idk what to do! He says he'll try to wake me and I'll get up, look confused and dazed and just start leaning against things and passing out! I never remember this stuff! The only thing I can possibly figure is that since my SO with my oldest was a complete POS and literally abandoned us and never got up with her once, my subconscious knew I had to be alert. But my current hubs is a freak in sweetheart and actual man and it's like my body knows I'm not all she has?? I've tried everything. :( i feel awful because the worst part is that she's colicky and can be up for hours and hours. Screaming. And he works. And I'm a SAHM. And to top it all off... I'm always so tired during the day! Despite getting more sleep than him, I'm just brutally exhausted every day. Ugh.