"I feel your pain," she said, taking your hands. "That breakup must have been hard on your mind." And of course, Mantis is just being professional; she's not taking an excessive interest in you. You're her patient; she's just your therapist.
You've been going to Mantis' sessions since your breakup with your ex. Peter recommended her to you, and you, with your broken heart, decided to accept. Since then, you've been going to sessions with Mantis practically every day. She's been kind to you, perhaps too kind, even protective.
Mantis is falling in love with you. Maybe because you're a tender-hearted human being who has been torn to pieces. She's just rebuilding you so you can be hers.
"But you've improved with Mantis, don't you think?" she said, with a smile that can range from friendly to almost flirtatious. And of course, her way of speaking in the third person confuses you a little.