Super anxious & antsy imho

so i'm new here & rlly anxious af. like,my bf said he's meeting his ex (they dated 10 yrs ago & she was preg wiht him but got an abortion) & i'm freaking out cuz i feel like he should've brought me or someone else along to make it more chill for me. now he says i seeem jealous & don't trust him, adn that feels unfiar since it's his ex who was preg & stuff. im so paranoid he might get feelings back 4 her & i can't handle hearing that from him after the meet up. ngl i'm scared to answer his call if he contacts me cuz i wanna know if he still just wants me or not, but saying bad means he has feelings for her again and god means it's all cool. i fel like i might have a panic attack during sleep & don't want him to notice cuz i'm afraid of how to explain it. alreay bought my ticket 2 see him next month cause he asked me to buy it. im trying so hard not to let this anxiety show but its' too much rn, especially about my bf who i love soo much. any ideas on coping & relaxing? like, if i do have a panic attack, how should i tell him or keep it hidden? im seeing my therapist wednesday but need help til then, cuz this is rlly stressin me out.