Breast pump issues

Hi mummies, This is my first time bf my baby. My baby latches for like 30-45 mins each side during feeding ( cause she keeps falling asleep till I rub her ears then she will start drinking again). I feel very exhausted cause of this as she feeding lasted for about 45min but in 2 hour time she’s hungry again. I consulted the lactation counsellor at kkh and they advice to pump out excess milk after each latching session so that can measure her intake. I bought a pump from shoppee but my nipples hurt after 10 mins of pumping. Any experience bf mums can help? I’m so clueless. Baby is going 2 months old and I’ve survived so far with 2-4 hours of sleep daily.