At 11 weeks, your son is fine! He will let you know how much he wants/doesn't want. He is starting to listen to his hunger pangs and full feelings. This s a great thing for him! It is perfectly normal for his feedings to come fewer and farther between. Just be prepared for his growth spurts and teething (hopefully farther down the road) when his appetite will increase.
My son started off at about every 4 hours and by the time he was 2 or 3 months old, he was already sleeping through the night! and that wasn't just a 6-8 hour stretch, it was 10-12 hours!!! Scared me the first time, but his stomach woke him when he was ready to eat.
As long as his pediatrician is not concerned (you should have a well-baby check-up soon), you shouldn't be!
I hope this eases your concerns.
May God bless you!
S.