Hi. Im On Nexplanon And Periods Been On Time Except

Hi. Im on nexplanon and periods been on time except these last 3-4 months havent had one. I have mostly all pregnancy symptoms but keep getting negative urine and blood test. Im feeling more movement and some what kicks everyday now. Did ultrasound the other day and she says she didnt see anything but I thought I did and felt like she wasn't even trying. My point is if its all negative than what else could it be? I have 2 kids I know what kicks and flutters feel like and its not gas.