Yes that would probably explain it! What a horrible, horrible story!
If her trauma goes that deep, you may probably never get her over it completely, but it is always worth trying, even if it may take months! Just take it very slowly, give her lots of praise and try to project as much loving and warm feeling towards her while you are doing it.
She'll probably always have a problem with the vets - being held firmly WILL trigger her trauma. Perhaps you could train her to sit still in a shallow box having her favourite meal while you check her and slowly get her used to being touched all over, even to having her front paws lifted, so, if possible you and the vet can eventually examine her without lifting her up too much while she's distracted with food? It may also help with cutting her nails!
Never stop talking to her and give her as much praise and encouragement as possible - piggies like it as much as any dog! And always try to associate new things with good memories. If she takes fright, step back, let her calm down for the day and go back to the previous level. I always have a treat for my pigs as soon as the vet stops with them, so they know when its over and they can relax.
Or you can use the walkie box for her to walk out on on your belly or the examination table.
But whichever way you choose, you will have an uphill battle on your hands and you will need a lot of patience and persistence. I admire you for saving her and hope that you can help her getting over her bad experiences and win her trust.
By the way, what is the name of your poor lady?