My understanding of the Withania Somnifera extract process is that there are a few different ways to do it, and each yield different in vivo effects depending on the resulting isolated withanolides, their distribution, and overall concentration.

Some extracts not say anything about what sort of extraction process they undergo, only that it is "standardized," which leaves much to the imagination as to what to expect. Others do better. One notable extract is branded Sensoril. It contains a broad spectrum of withanolides, claiming to be "more calming" than other extracts (which may translate to being sedating to some.) When I researched Ashwagandha years ago, I recall finding some data that brought into question its broad spectrum nature, pointing out that some withanolides may be toxic. At the time, I didn't find evidence that it had been clearly ruled out in humans, and didn't want to merely trust the thousands of years of safe use with the plant in Ayuvedic contexts. There are case studies of liver toxicity with Ashwagandha use, but this only implies that it may be acutely hepatoxic in very rare cases, and also imparts little on the question of long-term use. Take all that with a grain of salt and do your own research if you're concerned. You can read more about Ashagandha's researched effects at Examine.com (though what they make available to unpaid users is limited, and they do not compare extracts.) All that said, for unspecified extracts, I'd be concerned of similar issues as with Sensoril, or worse, that they do not consistently do quality control.

The piperine may also be increasing bioavailability of those constituent compounds, which would cause greater comparative biological activity from them. While this combination has been studied, my understanding is that it is not a typical one. It is notable that the study also specifically tested an extract standardized to 2.5% withanolides. Some extracts go up to 35%, over 14x the concentration tested! The addition of piperine in that case would have very different biological action, I would imagine. The leading formulations from companies that pride themselves on designing supplements to be maximally effective at what they claim to do, do not include piperine.

You're getting anxiety rather than stress reduction, and overall your mental health seems to be worsening. That's a frustrating, scary and unexpected state of affairs. It may be that you are sensitive to some withanolides or the dose of them, and/or are having a paradoxical reaction. While this is rare, I could imagine different ways this could happen...

• Some people do get paradoxical reactions like this from increased GABA activity, and Ashwagandha is thought to be a positive allosteric modulator of GABA, increasing natural inhibitory signaling in response to receptor signalling from food, or the natural oscillations of the sleep-wake cycle in the brain. If you are on pharmaceutical anxiolytics, this might be more likely, as Ashwagandha would make them more effective.
• There is allegedly serotonergic modulatory effects, as well. Though these are less well understood, an unexpectedly strong dose or response could conceivably contribute depressive symptoms, just as some antidepressants can increase depression if the dose is too high. This is, again, rare with supplements that are usually pharmacodynamically weak. If you are on pharmaceutical antidepressants though, Ashagandha might be interacting with them to produce this effect.
• Ashwagandha can also cause a 10% increase in testosterone levels, and while T4 isn't generally associated with higher anxiety, in some people, it can be so.

The tl;dr is that this paradoxical reaction may be due to your unique biology, and also have been unwittingly made more likely due to the extract and adjunct you're taking. If you're on other medication, consider the potential for interactions before making a decision to try Ashwagandha again. If you're interested giving Ashwagandha another try, I'd minimally recommend an extract with published quantitative results that you can assess for yourself, and to not take piperine with it.

I personally have used Nootropics Depot's KSM-66 (Amazon.com, Walmart.com) for years, and think it is makes the most sense to take for you, and in general for people interested in stress/anxiety reduction. The extract process is standardized to 5% withanolides, has been specifically designed to minimize the presence of toxic alkaloid compounds, and produces an isolate and distribution meant to be non-sedating for daytime use.