I am sorry to hear that your gilt is having trouble and there are no piglets, it could be that the first piglet is in the wrong position and blocking the way. I would be inclined to call a vet or if you are not able to do this how about a farmer who knows about pigs as they maybe able to help.
Has the gilt got milk in her teats that is coming out easily?
Has her breathing become laboured and is she nesting? These are all signs she is about the farrow.
If phoning for a vet or neighbouring farmer is not an option then if it was my gilt I would disinfect my hand and arm and then gently insert this hand into the pig and have a careful feel about.
As I said it may be that the first piglet has died and is blocking the way or the first piglet may not be fully formed and is blocking the way. If this is the case and the gilt is trying to farrow and there is a blockage then this could be dangerous for the other piglets and you may lose the other piglets and the gilt.
I would urge you to phone for professional help if she looks like she is having trouble or to even just ask the vet for advice over the phone.
Is the gilt manageable as sometimes gilts can become agressive when they are in pain so you need to make sure that you and any piglets are safe if she does turn aggressive.
Let us know how you get on.
sara @ farmingfriends