Words of encouragement?!

I've wanted to breastfeed since the moment I found out I was pregnant, but I feel like it's not getting any better. My son is now 4 weeks old and this past week has been the worst so far. I am afraid he isn't getting enough and I don't know what to do. He is constantly feeding every 30 minutes - hour. He never acts like he is full or satisfied, he can nurse for a good 45 minutes until I have to take him off bc he fell asleep. Everyone I talk to says it could be a growth spurt, but can growth spurts last almost a week?? I've read that the main way to tell he is getting enough is by his weight (which we haven't checked in 2 weeks) and by how many pee/poop diapers (He has plenty but the color looks a little darker than normal). Has anyone else been through this before, if so any words of advice? I really don't want to give up breastfeeding but I feel like everyday is worse than the last and I just don't know what to do.