This can be a difficult one, depending how bad your "panic" is.
I once had a student that flew ok, but panicked to the point of complete inability to do anything useful when experiencing turbulence and low G (let alone negative G). Examples included him hugging me when a wing dropped in a stalling exercise (very amusing) or completely letting go of all controls and bracing himself against the airframe when encountering a slight gust on short final (not amusing at all).
Together with the CFI, I developed a programme to make him [more] comfortable with this, starting with low-G pushovers to zero G and then unusual attitude recoveries until he was competent and, while not comfortable, well in control at all times. That took several hours of flying.
A few sorties later, something else [not low G related] spooked him so badly that he again lost it, so sadly in his case the problem was not low-G, but a propensity to panic to the point he could not control his actions [he couldn't even taxi the aircraft!]
As a flying school, we felt that was something we were not qualified to resolve, so we strongly suggested we stop wasting his money, which he did.
Based on that experience, I would say that it all depends on how bad your "panic" is, and if there is anything else that could trigger it.
If it is just low-G, perhaps focused training around that could help [it worked in that case]. That will require longer sorties, so if that is not possible in a glider, perhaps try it in a motorglider or - gasp - powered aircraft [go on, they are not all evil]...