Reaching the big o

I’ve never been able to finish during inter course and I know it’s been due to partners who don’t know what they’re doing but I’ve noticed whenever I use a vibe or my fingers for clit stimulation I think I finish but it feels like once I do I can’t keep going because it’s sensitive or uncomfortable. Is this normal? I know I everyone says to keep going but it doesn’t feel as great as when I first started the session

Thanks!