I'm a relatively new father, and I will say with full confidence that it just isn't that complicated. I'm not in grad school anymore, so I can sympathize with the added stress that would be. However, being a dad is minimal compared to being a mom. Just since a couple days ago my kid has learned to pull himself up and stand on two feet (with tons of help balancing). He gets up, smiles about how proud of himself he is, then sits down again, repeats. Sure it takes time, but fuckin-a it's not difficult. I sure do miss going to the movies pretty often, reading as much as I did before he was born, and traveling guilt-free, but those things are minor. If you want to be a good dad, then just be one. I can say from my experience that while I felt a deep sense of responsibility from the moment the kid was born, I didn't feel any profound sense of love. But the more time you spend with him or her, that changes pretty quickly.
When I found out my wife was pregnant I was stricken with anxiety, bewilderment, fear, regret, and I was already married and financially stable. You quickly realize none of that matters. Rich or poor, young or old, married or not, the only way to be a good parent is just to make a choice to be one. Your life will have some adjustments, but you're still you, you still have a full future ahead of you. Who knows? You may even enjoy it. Chin up. You're obviously a smart dude with a lot of life experience, you could make a really good dad, if you allow yourself to be. The one thing you always should keep in mind is that there is one thing every living thing on the planet has in common, and that's that none of us asked to be here.