Don't be discouraged. But let us look at it from a purely analytical approach.
It was bag seed. Bag seed is a kind of mystery gamble and this is why.
Bag seed most likely means it either
1)one of those sterile nanner types that develop later or one-off.
2) herm genetics.
3)some sort of open air grower who hopes they don't have lots of seeds
4)contaminated with pollen dust from other aspects of their growth.
Could be more but let us just throw it in that realm. typical growth or unintentional pollination.
1)If they were sterile manners. Not typically worth growing. But if they sprout you get something.
2)Lots of people dabble in strains that have herm genetics. that said some stable strains can have Hermes and the further you get from the source genetics the more this trait goes. So every set of bag seed potentially gets worse and worse. Or certain grower's genetics are more likely vs another breeders' stock.
3) why they can be a downfall is you may end up with males. you may not. If you arent expecting to deal with males it can be bad. if you keep an eye out for"regs" it's really not a big deal and you would know if this was the cause of seeding.
4) if it someone like me I only "open-air males and regs outdoors. so very reduced risk of cross-contamination. but higher risk of outside pollen. Can be mitigated with "greenhouses" So anything you would get in a bag from me as a friend would come from something with 95% potential it is going to be feminized seeds or nanners. My air scrubber setup was pretty great at doing it my new one will be better. So if you get someone that deals in female pollen and that's your bag seed. it can be a great way to get free fem seeds.(not that i deal. but if i did give you some smoke and it had one in my instance... again hypothetical)
but when you start to get into #2 and #3 as a generalization is you won't know if it's open air pollen from a herm, male, maybe not even true herm genetics, and some form of natural rodelization? so when you take that gamble it is really more for the experience. Not really to say you did anything wrong. Because you have no control of the source of the lineage of genetics and even then it can be a gamble. Some seed stock most certainly can be looking for the right pheno. Where you hear people mention getting 6 of the good ones in a fem pack. Some have variable properties where one might display its Indica side and another its Sativa side in a hybrid where the genetic you are after is the Sativa dominant pheno. SO even in high-end seed stock, this can still be a gamble. You're mostly paying for track record.
this is all hypothetical. But this is why people say don't bother with bag seeds. even when you get 10 bag seeds in some cases on stabilized strains. if they weren't intentionally pollinated. still can ring true.
So no one should feel down if plants do what plants do in the infinite realm of potential outcomes. At the end of the day, the goal is to see what cannabis sprouts up. But always take the time to analyze your environment to ensure You arent the environmental factor leading to inducing herm failure. Or unintentional pollination. This we can figure out hopefully 95% of the time.
edit: touched on stable and unstable genetics from good seed stock. Some people like super stables others don't mind picking through. So its not a negative to get a strain that has stable phenos but unstable showcasing. in that you get 2 or 3 dominant traits and looking for one. Cause all of them tend to grow into good smoke. But speaking purely to some unstable "monster" "various trait" genetics. One being fully stabilized doesn't make it a better genetic offering over another in the grand scheme. Just want to make sure i put that disclaimer in. I grow several genetics from "real breeders" that are unstable and love the strains. Eva Seeds Monster is one of my favorites. One has that extra big pheno that is the true monster you are after. When i grow it, I grow them out then do the whole clone cycle to see which one showcases the "monster" pheno to run. Not a negative when that's what i want. But i still grow them all out and they all are good smoke just one grows half the size of the other.