It will pass, I had the same problem and so did a friend, don't turn to pills as he did it just drags it out longer. Just keep at it, eat properly but dont feel bloated before a flight. By the time you have your PPL it will be a distant memory. Don't feel you have to keep quiet about feeling uneasy either, if you are doing steep turns or unusual attitudes and start feeling rough tell your instructor and move onto something else, your retention of lessons will be poor so dont push on till you can take no more just ask to move onto another aspect, maybe mention it in the briefing so you can decide what to work on if the other stuff makes you feel queasy. Once in the plane try to put it out of your mind and just get on with the tasks but don't ignore it if it starts to feel bad.