Pregnancy movements

Hi, so I’m 33 weeks pregnant and since about 29 weeks my babies movements have been very on and off. I’ve had to go to the maternity ward twice because I haven’t felt him move. They’ve all monitored him and the second the monitors on he starts moving. I’ve been sent for two ultrasounds and had blood tests but no reason as to why I can’t feel him like I should be. I try everything I try laying on my side, eating, exercising everything you could name! He has days where he’s moving non stop then other days where I’m lucky to feel one movement. Please help has anyone else had this???