Not sure if your priorities are loosing weight or gaining muscle?
The whole 'fat makes you fat' thing should have been lain to rest ages ago,
reducing processed carbs and eating more whole foods is the first thing to do. Walking and some resistance exercise is the second.
It should be possible to get all the protein that you need on a lacto-vegie diet (ovo-lacto is easier) but you can get complete protein by simple combinations of plant foods (like beans and rice)
-firstly, if you are not used to eating meat you will not have enough of the right bacteria to digest meat, and it will take a short while for their numbers to multiply to help digest the meat.
-secondly, meat quality....If your adding meat back do it slowly with small amounts of better quality meat
Susan2 is right, ham might not be a good choice, i don't know what quality it was and how much stuff was added to it - avoid meats with preservatives and color or flavor enhancers, particularly added nitrites.
Likewise if the ground beef was just ground beef then that's ok, but it is not uncommon for it to be mixed with fillers (even up to 50% in the worst cases).
Chicken and fish are probably easy on digestion
-thirdly, stomach acid and digestive enzymes,
you might not be producing enough acid and or enzymes, there are supplements (of which papain from papayas is one) but you might want to talk to a practitioner that you trust or read up on the subject as there are a few (for example
http://www.drclarkstore.com/digestive-enzymes-guide.html )