Hi Eryn! Welcome!
Don't freak out :) It takes time and practice to fully understand the core connection breath and activation. Essentially we are re-training our bodies to breath in a more functional manner and the breath/activation can almost feel counterintuitive until it starts to click. For me, it helps to visualize my pelvic floor and transverse abdominis (TVA) activating with my breath as I practice. On an inhale, focus on filling the bottom of your lungs with air, almost as though you are breathing down into your low back. Relax, and soften your core and pelvic floor as you breath in, then as you exhale begin to activate the pelvic floor first. One visualization that works for me, is to imagine you are sipping a smoothie with a straw up through your vagina (I know, kind of weird) as you exhale. Another visual cue is to imagine you are closing the 4 corners of your pelvic floor (pubic bone in the front, tail bone in the back, two sit bones on either side) in towards your vagina around something small like a diamond and then lifting that diamond up towards your heart. If you still feel like you are only doing a kegel (working the muscles around the urethra) and not including the entirety of your pelvic floor, you can play around with your positioning. Sometimes it is easier to locate and activate the pelvic floor, while lying on your back with your knees bent up, feet flat on the floor. Try the diaphragmatic breath from this position and see if you notice any difference in pelvic floor activation. Another option is to start seated on a block and lean backward with your hands supporting you from behind. Notice if you can feel activation towards your tail bone from this position. Then try the same thing leaning to the right and then to the left, again taking note if you can feel more activation in the direction of your lean. Finally, the way you are exhaling is super important. Make sure you are creating an audible sound (like the hissing of a snake). Pressing the air out from behind our teeth, naturally activates the TVA without creating a sucking in or bracing of the abdominal wall. You can feel this by placing your hands on either side of your belly with your fingertips pointing in towards your belly button. Take your deep inhale as your ribs expand out you will feel your hands move with your belly outwards, then use your resisted exhale, pressing the air out from behind your teeth. You can feel your abdomen start to gently draw inwards as the intra-abdominal pressure decreases.
I hope this is helpful! It's a lot of information. Give yourself plenty of time and patience as you practice and we are always here if you have any other questions!