Implanon and pregnant ?

Is it normal to get cramps and stomach pain but have no bleeding/periods on implanon? For the last 2 months my period has come almost every 1.5/2 weeks but now it has been 4 weeks since my last one and I’m experiencing a lot of stomach pains/cramps but no sign of bleeding yet (it will be 28 days tomorrow since my last one). For the first 4 months on the implant I either had a period every day for a month and then none for 2.5 months so I know periods are irregular on the implant but I keep freaking myself out and googling my symptoms and going crazy. Help?