Does this sound like a supply issue?

[Jakeyblueblue]

Ds is 11 weeks, he's been ebf since birth. Despite a rocky start due to him having laryngiomalacia (floppy larynx), we were doing great. 98th centile and gaining good weight. Infact supply was so good I was donating to milk bank.
Then at 8 weeks he got bronchiolitis. He was in and out of hospital but never Fed as they felt he was just about getting enough, although looking back his feeds were really quite a lot less than they should have been. He was so poorly and my 3 year old was poorly too, that i didn't have time to pump and that combined with the reduced feeds, seem to have really dented my supply. He did recover quite nicely and then seemed to ramp up the feeds and my supply struggled to keep up I think. He seems to be increasingly less staisfied and my let down has really slowed down. He gets fed up and fusses and the let down is even slower. My boobs are constantly soft and he seems to only gulp milk for a couple of mins before its evident there's no more to drink. I've topped him up with a few ounces of formula here and there but am reluctant to do that Incase it dents supply further. The only time I feel that my supply is good and he's having full feeds is in the night.
I'm an experienced breastfeeder, fed ds1 until he was 2.5 and have tried everything. Fenugreek, pumping Etc and have hung on in the hopes supply would increase on its own but I can't see any results.
He's feeding 1 -2 hrly and draining both breasts very quickly. Do you think this sounds like a supply issue or more that he's snacking so often breasts are empty most of the time? He's having lots of wet / dirty nappies. Can't tell much from weight at moment as he lost when he was ill but they never re weighed him so I can't tell how much he's gained since. He's almost 15lb though so a big hungry boy. I want to trust my body can produce enough to feed him but I'm worried he's going hungry.
Also has anyone successfully mix fed? Am I on to a loser if I top up a few ounces after a breastfeed if I feel he's still hungry? Will this be the end of bf?
Any advice would be greatly appreciated.
Then at 8 weeks

Please ignore the last sentence! Typo!

I am a ftm but my baby has started feeding 1-2 hourly over the last 2 weeks or so (she's 10 weeks +) and the GP suggested it was a growth spurt which many babies have earlier but she's having later (she dropped from 25th to 9th percentile week 8 or so). Perhaps the illness delayed a growth spurt which he is now having a bit later? If his nappies are normal, he would certainly be getting enough liquid I guess. Anyway I don't know if you have a HCP you could ask but if it were this that would explain the empty boobs by day and night time feeds being more normal (though mine has ramped up her night times AND I still get full hard boobs. Oh well if it means fewer waits to see the HV every bloody week it's a good thing).
How frustrating they didn't weigh him after as that would have answered your question. :(

Plenty of wet/dirty nappies plus good weight = good supply.

You've had a shitty start with your poor DS so I'm sure you're very anxious, but you're judging supply on factors which are impossible to judge such as 'empty breasts' and let-down - the only way to know what he's actually getting is his output and his weight which are both fine. One to two hourly feeding is great, and so what if they're quick feeds? He may be very efficient at getting what he needs.

Remember that breasts are never 'empty' either. If you don't have a lot sitting there ready, milk is made from the bloodstream, so he'll always be getting something. Breasts are factories not warehouses.

I have a similarly chunky baby.

DD is 91st centile and was 13lb at 6 weeks. She is 10 weeks now. I won't have her weighed again (not a fan of weighing bf babies) so don't know her weight now.

I suspect that recently she is taking in less milk and is probably dropping centiles. She is happy and content in her reduced feeds. I just think that although she was born big, she will not naturally be big (my other three DC are not big) so is just starting to find her natural weight.

Could it be that your DS is finding his natural weight, which is lower than 98th centile?