help anxiety? dont know

okay so recently i have started a new job i was so excited for it but when i started my training today there was quite a few people there an my anxiety / nerve s .. got the better of me an i felt sick to the belly / gut an felt sort of constipated ( like sort of needing to poop ) but i didnt want to go ( the embarrassment 💀🙈 ) so i held on for dear life and i needed a wee but couldnt go because i needed to poop it was so uncomfortable for me and i dont want it to happen again ... an

ideas to what it is or means ( was it just nerves or something else help tips and tricks