as stated, you can change the amount of health you get with the option by using the custom trainer ability. Also when you level up, likely your health will reset to normal.
secondly, the weight option might be affected if you mouse over something accidentally or aren't specifically on the page using the instructions as directed before you hit the option button.
no idea.. i have played using the trainer for over an hour
Thats normal (well, not NORMAL, but still), and not the trainer. There is a very common bug where the game freezes when you open the inventory. There are dozens of posts on the steam forums. Ive started quicksaving (F5) just before i open the inventory, just incase.