Pinescript - Cannot keep the changed variable

Question

I am trying to write a simple code in Pinescript v5. I have 2 user defined functions to get the highest and lowest since a condition is met. I am trying to change the parameters of these functions once another condition is met and keep it like that there onwards. The below part of the code does this change when "trade = true" for that bar only, and the next bar it calculates again from the initial parameters of the function. I want to keep these parameters changed and kept it like that. (so 'new_week' needs to change into 'trade' within the function once the condition is met and kept as 'trade'). How can I achieve this change to be permanent instead of one bar only.

GetHighestSince(conditionH, series) =>
    var float highestValueSince = na
    if conditionH or series > highestValueSince
        highestValueSince := series
    highestValueSince

GetLowestSince(conditionL, series) =>
    var float lowestValueSince = na
    if conditionL or series < lowestValueSince
        lowestValueSince := series
    lowestValueSince

float HighSinceCrossWeek = GetHighestSince(new_week, real_crossed)
float LowSinceCrossWeek = GetLowestSince(new_week, real_crossed)

buy = ta.crossover(real_crossed, (LowSinceCrossWeek + 2))
sell = ta.crossunder(real_crossed, (HighSinceCrossWeek - 2))

bool trade = buy or sell
plot(trade ? 1 : 0, title = 'trade')

if trade
    HighSinceCrossWeek := GetHighestSince(trade, real_crossed)
    LowSinceCrossWeek := GetLowestSince(trade, real_crossed)

Probably I am missing a very basic point, but couldn't sorted that out...