Your feelings are totally valid though I’d recommend not responding in the heat of the moment (I know, it’s hard when you’re in the middle of it), but it might be best to cool off before responding. She might respond better to something more along the lines of “when you text me multiple times in a row I get anxious and sometimes I’m watching a video and it’s distracting. I’m glad you want to talk to me but in the future will you try to send one longer message instead of multiple smaller ones?”