I have been doing this fitness stuff a little while now, as the name may imply. I am old enough to have grown out of doing stupid things and trying to make myself ache every day of my life, but somehow despite having taught moderation many times, before I became soft office boy, I've never quite managed to learn it.
My background is being the really short scrawny kid who grew up to be an average height scrawny adult who just happened to find himself deeply entangled in free climbing and a few other activities that supported it, including ballet. Over the years I have done a number of things including triathlon, boxing, aikido, ballet, contemporary dance, weights to make me prettier, followed by powerlifting. Now with full time job and family I aim to run 3 times a week, do 1 interval session and 3 weight sessions, squat, bench and deadlift focussed. I manage it when I can. My fitness has become far more part time as spare time has become such a rare commodity, but there is a theory that I may get to retire one day, though with the age continually increasing in the UK I may be 80 by then, when I will have spare time to be able to get back to more training.
Somewhere around the bodyweight forum you will undoubtedly be able to find a link JustinRVA used to post often about a batch of bodyweight movements that are good to use.
Difficulty with this stuff is always balance, the legs find handling bodyweight very easy while your upper body doesn't. This leaves you able to do squats until you lose count 5 times and fall asleep while chins and press ups are far quicker to tire you out. There are ways to increase intensity for the legs, adding impact, lack of injury allowing, single leg work, painfully slow movement or insanely fast etc.
Plyometric is great for this if you can do it safely. People will tell you off for not doing complete movement when doing it right but it is great for intensity. One of my classic fails doing this was jumping over a stack then doing a long jump straight after. The jump over the stack was just prep, the plyometric part was the instant take off as part of the rebound. Cuts the reps you can do down a treat. I had targeted myself a set of 5 as final set, done that and decided in my arrogance and stupidity that I should try another one when in truth I knew I was too tired. Inevitably I clipped the stack, but not just a brush with a toe, hit squarely about an inch from the top with both feet, sent the stack tumbling and landed on them splayed out on the floor. Got up wondering if anyone would have noticed, saw around 40 to 50 people nearby had and were displaying looks of concern through to laughter, so I took a bow and cleared up the mess. Age doesn't bring wisdom, I have survived despite the stupid things I have done.
That is indeed heavy duty calorie counting as Goldie said. Ironically considering how detailed this is I am going to raise a possible thing to add to the list, liquid intake and calories. You have listed milk once and may be like me drinking virtually nothing but water and lots of it, but I see many people ignoring this part of their diet, especially with concerns to alcoholic beverages. When you have put in this much effort to be so thorough it is worth going the extra step.
My intake is around 3,500 to 4,000 calories a day but I wouldn't have a clue where about in there it is day to day. I just know that fuelling the 13 stone person I have become especially when going for a lunch time run burns 700 calories in between 40 and 45 minutes requires serious food intake, something I used to find harder than I do now.