Is this anxiety/panic attacks?

I've always dealt with anxiety and also had therapy for a couple of years and then stopped because i was feeling good enough to be on my own, in the last 2 years i was doing really good and had little anxiety, i haven't worried about anything recently but now out of nowhere i'll randomly get a fast heartbeat that gradually gets faster till i can't bear it anymore and makes me cry uncontrollably, after this it goes completely away, i'm not having bad thoughts or anything it just happens, is this like a panic attack or what? I've never experienced this and i don't understand why since there's really nothing bothering me except having little to do since it's summer, i'm considering talking to the doctor about this cause it's basically happening every week, also it gets worse when i'm tired like after i had a long walk so i was maybe thinking if it could be triggered by some tachycardia instead of it actually being just anxiety, i was wondering if anyone experiences the same thing and what can i do to calm down when it happens?