I am sorry to hear that your kitty Tula is breathing hard (panting) with her tongue out, howling and unable to settle.
This could signify severe nausea or anxiety/stress or if the color of her tongue and gums is blue/gray or very pale that can signify difficulty breathing/exchanging oxygen.
Either way cats don't efficiently exchange oxygen by panting, so they don't do it unless things are very bad for them or they are extremely stressed.
If this was preceded by a very stressful event for her, she has only been doing this for a short time and her color is fine, then give her 10 minutes or so to settle down, try to comfort her and speak calmly to her and see what happens.
But if this has been going on for a while, if she has vomited or has attempted to vomit, and/or her color is poor (blue, gray or white), she has facial swelling or hives, then it is time to seek emergency care.
Please let me know if you have any further questions.