Breast pump support please 😢

Hey ladies, I'm looking for some advice. My daughter is two weeks old and is exclusively breastfed, however, I'm now thinking about pumping as I'm exhausted being up at nights and would love it if my hubby could give me a hand with these feeds, especially now that he is going back to work after paternity leave, I feel like I'm doing this all on my own. I'm just a bit apprehensive about pumping, I'm worried I won't be pumping enough to satisfy her. Obviously I have no idea how much she is taking from me so have no idea how many ml/oz I would need to fill a bottle that would keep her going until her next feed.. We're feeding on demand, usually every 2 - 2.5 hours, is this how long a breastmilk bottle will keep her going? If I leave her for a day with dad would I need enough milk to cover a feed every 2 hours? When should I pump - from the opposite breast during a feed each time or just every so often? And is it better in the morning, afternoon etc.? This so confuses me and I just want to be getting it right so that we are all benefitting. I hope these silly questions make sense 😢🙈