fussy baby

Tanya
My gorgeous little girl is so precious to us after loosing a little boy a few years back, we are besotted with her! She's perfect in every way!..
Apart from her feeding, she's nearly 4 months now and still feeds like a new born... every 4 hours!!
I've tried everything from trying to feed more often to stretching it out for longer periods, changing to faster flowing teats etc...
She knows what she wants & doesnt want! 
Nothing seems to make a difference, feels like this is going on forever... I know it won't, but a full nights sleep would be nice!
She's putting on weight but slowly so the health visitors are not overly concerned. 
Any advice or tips you could recommend?.. 
routines are all good but she has her own routine & don't look like it's going to change anytime soon! 😬