Have the previous years at the pig roast been fun? What was it about last years that wasn't so good? (other than being the time you started to have bad dreams)
Would it be worth focussing on the good years and how much you've enjoyed them?
Your family sound fantastic and very supportive. You haven't let them down in the least by revealing your fetish. If anything you've created a stronger bond with them for showing them how much you trust them and for letting them help you. If you were my son, I'd be so proud of you for coming to me with this and I'd want to help you in every way I possibly could.
As for yourself. Take a look at where you were last year and then take a look at where you are now. Ok, you're not 100% happy and bouncing off the walls, but I think from reading this that you've come a long way. It's an uphill climb (isn't everything?) and with the right help you will get there.
I think there are two ways of looking at the diaper wearing for this weekend:
1. Will you be too scared of anyone possibly noticing to fully enjoy yourself? If so, don't wear one this time and get a little more experience and confidence in wearing them around other people and leave it until next year.
2. Do you need to wear them to help you cope with the day and the bad things associated with it? If that's the case then wear them. Everyone will be too busy looking at your smiley face and wondering what your secret is (I mean in general terms not fetish) and they'll never guess unless you tell them. And let's face it, they don't need to know anyway.
You need to do what you feel most comfortable doing.
Incidentally, I just looked up the meaning of suicidal dreams (I don't know if you believe in all that) and it's actually nothing to do with suicide. Yes it can mean that you're depressed, but it can also mean that you're ending one chapter of your life and possibly having trouble moving on. Or even that you did something that you regret. Not so bad after all eh?
I honestly believe that you need to speak to someone that knows all the right questions to ask you. That's what the professionals do. They ask and help you to figure out what the problem is that's holding you back and making you feel this way. They are there to help you and although they may seem like the enemy at times, really they're not. Give that number your pastor gave you a call and then give yourself a big pat on the back for taking such a big step.
Other than all of that, you've got all of us backing you up and wishing you a lovely weekend and future xx