As several people have said, the original (with a comma) is perfectly grammatical. However, when you switch it around, it sounds better with "on." >To the point that I became dizzy, I kept on studying. but I'd be more likely to reword the switched-around version with an "until" > Until I became dizzy, I kept on studying. or, maybe keeping closer to the meaning of the original, >Until it made me dizzy, I kept on studying.