Weight loss patterns

So... I'm doing great over all with weight loss but the way I lose is odd. Mind you I've been on this lifestyle change for 4 Months. I just eat right minimal carbs, no processed foods..lots of greens and lean protiens and work out. I've lost 40 plus pounds so I average 10 pounds plus a month. Now.. when I lose its like a pound plus a day for 7-9 days then nothing for like 2 weeks. Then boom I drop again and repeat. Is this normal? Thanks everyone!