I think the trouble with grapes is the pesticides, at least for me. Conventional stuff always causes me issues, while stuff labeled organic from a farmer's market does not. I've got the same issue with cherries.
Since you've taken antibiotics, clearly your gut flora needs replacement. The usual stuff applies: kefir/yogurt (make it yourself for best results), sour kraut, pre-biotics, probiotics, etc. Once you've got that squared away those, you'll notice a huge improvement.
Another thing to worry about is whether or not you have the proper acid levels, which you can test with Betaine-HCL or digestive enzymes. You'd worry about this if you're having a meat only meal and it feels like it just sits in your stomach like a rock and doesn't move. In that case, on an empty stomach take a pill, one at a time, upto no more than 6 and put your hand at the top of your stomach and feel for heat. Once you feel heat, that's the dose you should take. If you don't feel any heat and you've reached 6 pills, try eating a meal right after that and see how you feel. (Don't take these pills on an empty stomach and then skip a meal as you might get acid reflux - always eat something with protein after you do.)
Note that this will change once you start to properly absorb minerals like zinc, magnesium, potassium, etc. which are needed to generate the proper acid levels. You'll want to supplement with these as well, at least until you're healed.
As for yeasts vs bacteria, if you have bacteria, going Very Low Carb/Zero Carb will eliminate them. With Yeasts, it's the opposite, you want the good bacteria to fight off the yeasts as yeasts have mitochondria and can eat ketones/fats. There's an episode of Chris Kresser's podcast where Paul Jaminet is interviewed that they go over this stuff, highly recommended listening. I believe it's this one.
Also cashews are probably something you want to avoid, if you can afford them and find them, try macadamias instead. Cashews aren't nuts and they've got a high n6 PUFA content.
Also see if you've got a sensitivity to FODMAPS.
The spots on your skin sounds like you have an allergy to something, so you'll have to work at it to find out what.
Try some L-Glutamine and see if that helps, in addition to it's carb craving silencing qualities, there's some stuff out there I've read that says it helps heal digestive issues.
Another thing to use is coconut oil as it helps us with leaky gut and is a very easy fat to digest incase you've got bile or liver issues. Plus it's antibacterial, but it only kills the bad stuff. Try a little bit of it in your coffee (or tea) each morning and work your way up to a tablespoon a day at most. If you do too much at once, you'll get the runs, so start slowly.