If you breastfed for around a month you may have stopped around a major growth spurt, there's one at 3 weeks. They do constantly feed during growth spurts, it's their way of building up your supply so you'll be able to feed a bigger baby with a bigger appetite
If there were no problems like weight loss or dehydration then your supply was most likely fine, so I wouldn't be worrying about supply next time round. Very few women suffer from low supply on its own. What I mean by that is that low supply can occur if baby has a tongue tie for example, or formula has been given here and there meaning that baby's signal to the breast to make more naturally hasn't been received. But low supply on its own is rare.
Pumping is not the best indicator of supply. I can only pump about 2-3oz in one sitting and my LO takes about 7oz in one feed! Baby is much more efficient at getting milk out than a pump.
It's very hard because we don't have a measuring jug on our boobs
But if baby seems content, has plenty of wet and dirty nappies and is gaining weight, you have no issues
There are growth spurts when baby will feed seemingly constantly for a couple of days, maybe up to a week. Cluster feeding is also very normal, so a couple of hours of being on and off in the evening. My LO cluster fed up until about 3 months old every evening.
It might be worth just reading up on typical breastfed baby behaviour so you know what to expect. I get where you're coming from because when I had my eldest I had no bloody clue and I quit after a few days. Second time around I read everything I could so I knew what to expect and hey presto we're going strong at nearly 9 months