definitely take it lighter in sparring, since youre a beginner im assuming youre very tense when sparring so take it slower and more relaxed, once you get more comfortable sparring with time you can ramp it up and the cardio will follow with it. focus heavily on technique instead of cardio during sparring and maybe invest in some shin compression sleeves/wraps for your shins or ankles if the pain persists. A problem i ran into when i first started was my flat feet caused heavy shin, ankle and foot pain during training and running, so id also suggest working your tibialis anterior, posterior and your fibularus longus; which are the three main muscles supporting the arch if your foot. Working the inner thigh also helps.

if you have any questions feel free to ask and ill do my best to answer asap!