Are you saying that you have so much liquid, and you are wearing a pad, that it travels upward after filling a pad?
Yes it's normal. Buy the biggest pads you can find. The purple always I think is the largest.
That heavy flow is so annoying, have to sleep on our sides and even then it still flows out.
If you don't mind this. Try using adult diapers with a pad or without. And just wear them during the first few heavy flow days . They help in keeping the sheets and pyjamas clean.