Ah, worried pokémon. I’d hate to say it, anonymous, but it’s heartwarming to know a pokémon cares that deeply about its trainer. The bond between the two of you must be magnificent!
That having been said, as always, start slow. Begin by sitting. Sit upright with your feet on the floor. When your machamp begins to look worried, speak to her in a reassuring tone. Let her come close and have her reach out for you but not touch you. If she picks you up, ask her to put you back down wherever you were sitting. Ask her, not order her. Ordering her may exacerbate the situation.
Once she reaches out for you, take her wrist and pull yourself to your feet. If she panics and picks you up then, ask her to put you back down, as you had earlier. (As in, ask her to seat you, not place you back on your feet.)
Keep doing these two steps until she allows you to stand. Once she does, allow her to walk with you. Let her support you as you walk across the room at first but gradually work your way towards shifting your weight so that you support yourself. Once she realizes you’re walking basically on your own, pull away from her a little and show her that you can walk.
If you perform this process gradually, you’ll eventually work your way up to the point where she trusts you to stand on your own two feet. Once you remedy the immediate process, you can begin to work on the deeper issue, which is the fact that she seems overprotective of you. This can occur for a variety of reasons, including issues that were born from her former trainer (assuming she had one, considering she’s a machamp and not a machoke). It’s important to isolate what it is that’s causing her anxiety and see if you can find a way to reassure her and to convince her that she doesn’t need to be afraid of losing you.
Best of luck, anonymous.
The Pokédex According to Bill 