Please don't take offense to this as I'm only stating how I feel from what you vented on this forum.
You gotta breath man, first I think like others stated here you don't know all about the business and I think this is stressing you out. I think a lot of good advice was given to help you, but I also think you are doing a lot of great stuff to.
As far as getting low balled, reselling ect... It's part of any small business where prices arent really set in stone. ( I never low ball but I do try to get some what of a better deal if possible). I'm 26 and if you think lowballing is bad in snakes try hearing your dad talk about people coming in and trying to do that on cars for 22 years of your life. ( He owns 3 car lots).
Anyways I think you just need to remember that at one point this was your hobby before a business. tbh I think you need to hold back on some BPs and not get stressed from this and worry about business later and just sell to sell.