Increased Heart Beat, Intense Fear, Nausea And Dizziness After A Dejavu. Cause?

I keep experiencing intense deja vu, this has increased significantly in the last few months or so. I get this feeling of warmth and familiarity which is then followed by an increased heart rate , intense fear which is almost unbearable, nausea and dizziness . It mostly passes after about a minute but I do feel strange for a while afterwards. I am taking sertraline and have been doing so for around 1 yr (no side effects apart from yawning and some nausea right at the start), I was diagnosed with depression about a yr ago but was fully discharged by the community health team late last year after a course of CBT ...my meds are also reduced...the last reduction was around 5-6 mths ago (from 150 to 100mgs). I do not take any other medication. I ve just had one of these turns and feel very hot and a bit shaken and tired now. I ve had 2 today so far. I don t feel scared of the dejavu, it s like the anxiety & all the other symptoms just come with it, I ve tried to explain it to people but it s very hard to describe, what do you think could be causing this?