Hiya & welcome littlelugs
As Sally says, it's impossible not to get attached to them & I echo what she says about the fact that they will have a lovely life with you, so don't feel bad about it. I cry every time we go to the abbatoir with ours, but it's why we keep them & they wouldn't be here if not.
In preperation for "the time" - visit your abbatoir well beforehand, ask to see round, find out if they have a specific day for pigs, some restrict what weight they will take, whether they accept ear tags & what types, or slap marks - you will have to order your equipment well in advance - you will probably have to practise reversing your trailer too
Remember there are welfare standards as to what you can use to transport pigs - the abbatoir &/or your animal health inspector can guide you on this.
Have a chat with the manager about slaughter cost & butchery while you are there, it's helpful to have a face to a name too. The manager may have a link to or recommend a butcher. You may want to have a chat with some of your local butchers too (unless you are going to do that yourself & only supply friends & family) - you will need to discuss what type of joints/sausages etc you require. Some of them will pick-up from the abbatoir, which, if you are selling to the public keeps you right with the regulations. You never know, if they see your pork, they may ask you to supply them
Oh & talking of regs make sure you have the correct movement paperwork - again check with the abbatoir, some of them will want you to use their forms rather than your local authority ones.
Congrats on your first litter, good job with the AI too