I had something similar happen to me about a year ago.

I had just really started opening up to my T and had to leave town for a few months. While out of town, I started experiencing intense flashbacks, most of my days were filled with re-experiencing all the trauma I'd ever gone through.

For me, it helped to journal, write everything down I experienced and have my T read it. That relieved the pain in the moment until I could see him more often again.
After seeing him on a normal basis again, it still happens but to a much smaller degree.

I think what's important to realize is that you shouldn't just talk about the past every time you're in session. It's not helpful to just go over your trauma again and again. That will retraumatize you and it doesn't solve anything. My T at one point said that he felt we spend too much time in the past. I got angry at first, but I get what he meant now.

Currently, I sometimes talk about trauma, maybe twice a month or so (I have 8 sessions a month). If we talk about something happening in the present and it has some connection to the trauma, my T will mention that. He helps me see how it affects me in the now, without going into detail about what happened back then. I think having this kind of balance is important.

Does your T not want to talk about the trauma anymore at all, and just gives you techniques to think positively now? And what has he done before that when you discussed the trauma?
I think it's certainly possible to be retraumatized, but there's also the part to therapy where you sometimes get worse before you get better. To decide whether you should talk to your T, find someone new altogether and whether or not the issues are really getting worse on a constant basis, I think it's important to look at how your T is working with you. Does he make connections between different things for you, does he try to encourage you to not only talk about the trauma while still being accepting of the fact that you struggle with it a lot and therefore feel the need to sometimes talk about it?