I don't know the answer to your questions but I suggest leaving AP for after giving birth to your child. AP is safe in most cases but there are bad experiences too and since we don't know how exactly it can affect you and your child's health it's better to be safe than sorry.
As for how it affects AP, my blind guess is that probably pregnancy somehow affected your ren and chong meridians and opened them up and caused the qi to ascend but probably now at this stage your qi just shouldn't go that way and it might interfere with your stomach's qi in going down which would explain the pain in your stomach.
Another reason that I can think of is that in the process of pregnancy and especially after giving birth your body would consume a lot of your yuan qi which is the vital energy source for AP. In that case is would be normal to loose some of your abilities as a result of loosing your vital energy. However if after giving birth you rest enough and gradually condition your body through diet as well as moderate exercise you might be able to restore most of what you have lost in a short time.
As for how it affects AP, my blind guess is that probably pregnancy somehow affected your ren and chong meridians and opened them up and caused the qi to ascend but probably now at this stage your qi just shouldn't go that way and it might interfere with your stomach's qi in going down which would explain the pain in your stomach.
Another reason that I can think of is that in the process of pregnancy and especially after giving birth your body would consume a lot of your yuan qi which is the vital energy source for AP. In that case is would be normal to loose some of your abilities as a result of loosing your vital energy. However if after giving birth you rest enough and gradually condition your body through diet as well as moderate exercise you might be able to restore most of what you have lost in a short time.