stomach being hard for hours non stop

The yellow tint to the discharge is nothing to worry about. Do mention it to your doctor the next time you see them though so they are aware. I had a tinted discharge like that too and doc told me that's fine. Be careful and watchful though, if it goes a greenish color or has a foul smell (kinda fishy like) then go to doc right away. As you may be getting or have an infection.

The belly going hard is very normal. It's braxton hicks and false labour. What part of the belly going hard? whole? top? Tips to know if it's braxton hicks or true labour; when it happens and you can change positions, move, walk and the pain or hardness relaxes some then it's braxton hicks. True labour will not stop or go away no matter what you do, alway will form some kind of pattern and the harding of the tummy will come with cramps/contractions which will slowly become stronger.

All at the same time if you ever feel that it may not be right or really unsure and unsettled about it, go to the doctor or hospital as they can confirm things for you by doing a strip for you. Hope this helps and calms the concern a bit.