Oh my gosh. Totally understand. My symptom onset happened the same way yours did. It has been almost 6 months for me, and I still sometimes get confused. (But not constantly finally) Unfortunately, like mark has said, there is no way to measure when your symptoms will clear up. (but, i have also heard that you could wake up one day and be great...hasn't happened to me yet, lol )

As far as the tummy troubles, I had no appetite for a week straight after my most recent injury. It was like my brain was not telling my stomach that it was time to eat. That did go away after the first week.

When you get lightheaded standing up, (I did too, it could be because of the lack of nutrition since you are not eating, or to the concussion, idon't know, but) try to stand up slowly, or if you are standing from laying down, stand up progressively. (kind of roll to the side, and tuck your legs in, and do it slowly...at least that seems to help for me)

It takes time, but you will definitely learn coping skills to help you power through this. And this forum is full of great people with tons of advice and combined PCS experiences, so just keep posting and reading when you feel up to it!