Ovulation test.

So I've been using clearblue advanced test. Is it notmal to have 4+ days of "High" i have 2 apps that tell me 2 different ovulation/ fertile weeks. One says the week of the 18th another said this week. I also read where SOMETIMES a ovulation test can pick up HCG. Anyone else have this problem? One app says period is to statt this week and the other says the wek of the 15th. TIA!!!! 💜

Update. Took a first response and got a BFN.