Kate, Princess of Wales, 42, is still reportedly receiving preventative chemotherapy treatments for an unknown type of cancer, but her lack of royal appearances has many concerned. “Kate’s feeling strong enough to be very involved with the kids,” an insider told Us Weekly. “She’s been an active parent.” A second source near the Wales’ household added: “Kate’s recovery is going well. She’s not able to see many people because she is susceptible to getting sick and they don’t want her compromised, but she’s up and about.” In the last eight months, Her Royal Highness has attended only two royal en…