ixel - where abouts do you live ? It would be a good idea to see a bf adviser. Reading a book at this stage is ok, but I really think you need support from another bf mother or bf adviser.
At 3.5 weeks my son would have been feeding several times during the night - around 12 feeds in 24 hours. I am not saying that is what your baby should be getting, it's just a rough idea.
Also how often does he feed during the day ?
I have copied and pasted this from kellymom.com for you. Please read the stuff on this website until someone can help.
I am sure tiktok will be round shortly 
WEIGHT GAIN:
If baby is gaining well on mom’s milk alone, then baby is getting enough. A 5-7% weight loss during the first 3-4 days after birth is normal. Baby should regain birth weight by 2 weeks. Once mom’s milk comes in, average weight gain is 6 oz/week. If these goals are not met, call your lactation consultant. More on weight gain.
WET DIAPERS: 5 - 6+ sopping wet diapers per day (after 1st week).
Expect one wet diaper on day one, increasing to 5-6 by one week. To feel what a sufficiently wet diaper is like, pour 3 tablespoons (45 mL) of water into a clean diaper (if baby wets more often, then the amount of urine per diaper may be less). Urine should be pale and mild smelling.
DIRTY DIAPERS: 3 – 4+ dirty diapers per day (after day 4).
Stools should be yellow (no meconium) by day 5 and the size of a US quarter (2.5 cm) or larger. The normal stool of a breastfed baby is usually yellow and is loose (soft to watery, may be seedy or curdy). More on infant stooling.
OTHER POSITIVE SIGNS: After a feeding, mom’s breast feels softer and baby seems reasonably content. Baby is alert, active and meeting developmental milestones.