This is a little difficult. There are plenty of times where I'm feeling Debbie Downer and attending such an even feels like a major hardship, but I go, and it turns out to be a fantastic time and just what I needed. Other times it has felt like a chore, but this is more rare. I usually err on the "good times" aspect and attend. This one is all you. Given the last minute switcharoo, I think you have a reasonable excuse not to attend. You already had other obligations, sorry. If your dad feels it's that important, then he can attend. Seriously, I pulled this on my husband once when he got all opinionated on my attendance. You go. If it's that important to you, then you go. I have a test next week and I'm behind and I have work and I'm not going. You go. You go find the perfect gift, wrap it, show up, play the toilet paper game and safety pin game and socialize and have fun. I'm staying home. In my defense, I went through a nine month period where, no joke, I had a baby shower or wedding shower about every single weekend, plus the occasional BBQ, family meal, anniversary, or birthday celebration...I was seriously OVER attending one more event and buying one more gift. For hubby, how easy to be opinionated because he didn't have to be at 75% of these events.
As for the gift, even if the original Sunday plan was still in place, it doesn't sound like your gift is complete, you just had an easy excuse to not attend, bypassing the no-gift issue. I think a nice card with a picture of the work in progress enclosed (or IOU sort of written note) would be a good solution. You will probably have fun and enjoy mixing it up with people you don't get to see very often. I know I would very much appreciate a hand-made gift, even if it wasn't ready on the date of the shower. The hand-made gifts are such a treasure
. You really shouldn't be worrying about this one at all