Nose sinking whilst riding

G'day Guys
I have been making real progress lately since my ribs healed up, but have suddenly hit a what I hope is a small problem. I have searched the forum but can't quite find a specific answer to my problem.
I have been starting to catch green waves and riding better and longer but I tend to be sinking the nose whilst riding. Now I am only 5'8, 12 1/2 stone and am riding a 6'8' bigfish, 21 inches wide and 2 5/8's thick. (lots of hard work learning on but I am finally getting there)
I suspect it's foot placement or weight dispersal, but am struggling to adjust once up.
Any Tips/advice to help aleviate this problem. Would a rear pad help? I find it difficult to asses how far back my rear foot actually is.
I have been making real progress lately since my ribs healed up, but have suddenly hit a what I hope is a small problem. I have searched the forum but can't quite find a specific answer to my problem.
I have been starting to catch green waves and riding better and longer but I tend to be sinking the nose whilst riding. Now I am only 5'8, 12 1/2 stone and am riding a 6'8' bigfish, 21 inches wide and 2 5/8's thick. (lots of hard work learning on but I am finally getting there)
I suspect it's foot placement or weight dispersal, but am struggling to adjust once up.
Any Tips/advice to help aleviate this problem. Would a rear pad help? I find it difficult to asses how far back my rear foot actually is.