Sleeping Hell

My LG is only having one nap as she is refusing a second one but she is up every single night for sometimes hours at a time just unsettled, crying, won’t be left and it’s literally killing me off! Anyone else going through the same thing and have any tips - sometimes she sleeps on a morning and then has a long wake window and I know she’s then overtired at night but I don’t know what else to do if she physically won’t sleep on the afternoon! Any advice appreciated:)