Stressed out over breastfeeding vent :(

My son is 3 1/2 weeks old. Exclusively breastfed. I am super stressed out about it though. I constantly worry if hes getting enough. Then i second guess my self and think im over feeding him because he spits up frequently . he has been diagnosed with reflux that his dr gave a prescription for but he still spits up. I worry about my supply. I think i have an over supply because i have a forceful letdown. But lately feel like i am not producing enough because he is only eating for 2-5 mins within the last 24 hours... I just feel like im just not doing a good enough job. He sometimes eats for 5 minutes or less sometimes 10-15. I look at my husband sleeping peacefully throughout the night and i just resent him so much. Is this normal? Does it get better??? Please help :( i thought it would be easy by now that hes almost a month old...