Returned nipple pain after 2years nursing?

I’m currently 5dpo and have been experiencing slightly tender breasts and today my nipples are so sore. Like they feel as if it was the first time I’ve ever nursed(remember those times? 🤪). My son is almost 2.5yo and still nursing frequently. Did anybody else experience this? I’m trying to hold off on testing as long as I can but I can’t ignore these symptoms