Is It Normal To Have Spotting And Cramps After Having An Implant?

hi i've had the implanon implant for about 20 months now, initally i had a period for about 6 - 8 weeks but very light. and since then i have bled approx every 3 months but again extremely light. but recently i've been on a period for about 6 weeks now and is noticiably heavier. it changes from dark brown blood for a few days to bright red then back again. have experience a bit of cramping also. is this normal after do long?

i'm 35, obese and have type 2 diabetes