On May 15, the GBP/USD pair managed to break down the lower limit of the bullish BLUE channel depicted on the chart. Since then, the pair has been moving within the triangle pattern after having a quick bearish swing between 1.6300 and 1.5260.
Last week, the GBP/USD pair has found significant support at the lower limit of the triangle pattern around 1.5460 which pushed the pair to the upside for about 260 pips in one day.
Price level 1.5720, which corresponds to the upper limit of the symmetrical triangle, constituted an intraday resistance for the pair on the short-term as expected. However, breakthrough above it opened the way towards the stronger resistance zone 1.5773-1.5840 which expressed its bearish pressure quickly.
The GBP/USD pair has come back to consolidate within the depicted triangle again allowing the pair to make some bearish retracement which can be observed more clearly on the 4H chart.

This week after stepping above the price level of 1.5720, the GBP/USD pair was testing the backside of the broken limit of the triangle and the broken resistance level of 1.5720 which failed to hold price above.
Price zone between 1.5773-1.5840 constituted a supply zone which was expected to bring bearish retracement towards 1.5600 before further movements can take place.
Bearish retracement was expected especially after this quick bullish movement. This bearish retracement was confirmed with 4H closure inside the triangle again (below level 1.5667) which confirmed the reversal Head & Shoulders pattern depicted on the chart.
Now the GBP/USD pair has an important support zone located between 50% (1.5612) and 61.8% (1.5575) a Fibonacci level which is expected to bring a bullish move to the market. However, breakdown of 1.5570 extends the bearish retracement towards further target levels, that's why SL should be located below 1.5555.