How to convert windows LDM to GPT without loosing data

I was using boot camp on my Late 2011 MacBook Pro and I needed more space, so I followed this tutorial https://www.partitionwizard.com/partitionmagic/reszie-boot-camp-partition.html

but when I combined the 2 partitions in windows 10, it said to restart it, so I did, but it kept BSOD with the error message relating to an invalid boot partition. So I thought so what, there was nothing really on there ill go back to using OSX, but when I went to select the boot drive using option at bootup, it wasn't there.

I went into Target disk mode and hooked it up to a mac mini I have and the whole drive is now Windows_LDM partition.

Does anyone know how to convert the main partition or the entire drive back to GPT so I can boot into OSX again without losing data? I don't care about the windows partition, only the OSX partition is important. Or make it so I can access the data on it and at least create a backup I can restore from later, or just get the important stuff off/

I have no backups or anything. I do have the mac mini to use if need be. I also have a windows PC running windows 10

I have tried booting into recovery mode using command + R but only get internet recovery. I removed the original HDD and installed a 240gb SSD so I don't know if there even is a recovery partition on it. No recovery drive shows up in the boot menu either.

Specs

Late 2011 MBP 15" A1286

Core I7 2.2ghz

12gb RAM

OSX High Sierra or just Sierra, Im not sure if I upgraded to HS

I'm pretty good with computers, but I'm not the best with terminal and its commands.

Also, I know I should back up my computer, but I didn't think it would have damaged my OSX partition when resizing it. If there is no way to do it without reinstalling, then it is what it is. I would like to save the data, but if that's not possible its fine.