I didn't post my analysis from last week but I will be posting this one, this is basic supply and demand America has printed more money they have supply and the Dollar is the world currency for exchange so there is demand for it, now people are buying USD and selling their currency that's why there is a drop
And also GBPUSD hit a resistance on Monday night and and started to fall price as rested on a support (1.34551) and as history is going to repeat itself the support was previous resistance meaning it has been broken through before there is weakness around that area, at the close of today's market price is seen to be going for a retest on the H1 TF