Bp of 90 and fever of 38.6 on chemotherapy treatment . can this be sepsis ?

Concern: It's definitely concerning. While I can't say for sure it's sepsis without other information including a blood culture and other information, it's possible you could be on your way to sepsis, especially given the fact you're on chemotherapy. I would highly suggest you get in touch with your treating physician or his/her on call physician this afternoon and discuss your symptoms with them.Good luck