breastfeeding question

Long story short I stopped nursing around 2 weeks and exclusively pumped. I recently tried nursing again at 5 weeks and it seemed to go great for a few days. Now I'm wondering if she's getting enough. If I pump after she eats I get 3oz total which is what I would get before I started nursing again. So question is it possible for her to "look" like she's latched and feeding for 15 mins a side and actually not getting any milk? I just bought a scale on Amazon to try to weigh her to find out. It should be here tomorrow but I have major anxiety. Last night I fed her some expressed breast milk from a bottle after nursing because I didn't think she got enough to eat. Please help!!