I can't say I've been in a similar situation so I don't exactly know what you're going through. I would, however, recommend that, if your goal is to make progress and to get stronger, don't wait for it to get easier.

Don't step "down", step up. Do the thing that makes you feel like you're going to die, and then, a few weeks later, when it makes you feel like you're going to puke, step up again.

Sharp pains are bad. There's something wrong there that you need to get checked before you progress. Otherwise, I'd say figure out a way to make it work and suck it up.

Can't handle full body weight dips then do them off a chair with your legs straight out in front of you. Still can't handle that, then bend your legs. You can keep bringing your legs in until you have them doing most of the work directly under you. (This was just an example. You shouldn't be doing motions that cause sharp pain)

If you're arms are collapsing when you dismount, stick some pillows under your head and and aim for 10 more seconds before you collapse today. Keep doing that until you don't collapse. Then aim for the same amount of time but instead of collapsing, lower yourself down, then 1 down and up, then 2, then 3 and keep going .

With body weight exercises sometimes there are big jumps from one thing to the next that require a lot more strength to accomplish. Modify it so that the next thing is still doable but much harder. If you keep stepping back you won't ever reach your destination.

Doh! Sorry, I thought I answered this days ago.

I'm not sure what you mean by rough form . . . My experience with body weight training is that you can either do it or you can't. And if you can't there's a step down version of it.

For example push-ups - Start with a wall and do wall push ups, once you can do those, move to stairs so you're on a bit more of an incline, then move to the floor on your knees, then off your knees, then clapping, then one armed. Some where along that progression you can do the exercise with decent form. If what you're saying is that your form sucks when you try and do push-ups off your knees then I'd say go backwards not forward, and increase the reps until you're weak and shakey and fall on your face. And then go on from there. Do 5 more reps next time and then 5 the time after that until you feel like you can make the jump to the next level with decent form.

Once you do jump up from one to the next, you do not have to have perfect form. The very first clapping push up you do, should end with you terrified at how close you came to smashing your nose on the floor. But if your form is soooo bad that you do smash your face into the floor, then you're not quite ready to move up yet.