28 weeks pregnant and feeling a weird beat in my belly

Lucia
Hello, I am 28 weeks pregnant and for the last few weeks I've been feeling and seeing a weird beat in my belly, it is slower than a heart beat, too faint and too Constant to be hiccups. I am a little bit worry about this, I can't think on anything that my baby could be doing in my belly to cause this. I thought maybe he is practicing breading already, but the beat is too fast for breading and I feel it like a beat. It is rithmi beat, and ia not always in the same place of my belly either, it is kind of like hiccups but only too constant. Have any of you feel this? Does anyone knows what this could be? Please any opinions would be appreciated.