Congratulations on losing 5.5st!!! that is fantastic
Weight loss will slow down as you get nearer target, you could try changing what you eat, we can get into a rut and go for the same things all the time. Up the exercise or change the exercise u r doing. Make sure you are drinking plenty, keep a food diary, if none of this helps then look at portion control. I am sure others will be on here and give you lots of more info than me