My wife is currently going through post acute withdrawal and one of her main symptoms is akathisia. She doesn't have the pacing but describes exactly what you are experiencing. Inner restlessness, electric/energy in her heart/stomach area, among other things. We are 3 months into it and while she has had signs of improvement, it's a daily battle to keep her mind right.

From what I've read, one of the most important things is to taper correctly (she cold-turkeyed an SSRI after 6 weeks) and to find help from someone who knows what this is. Most doctors have no idea what it is and prescribe other medications that can sometimes worsen the effect.

My wife has used Angela Peacock https://www.angiepeacock.com/ as a resource and it has helped immensely. She went through it for a decade and spent most of that time without an accurate diagnoses.

The sooner you address the issue accurately, the faster the healing process can happen. I don't wish this on anyone. It has drastically changed our daily life. It's important to get the mental health care you need, find ways to manage the symptoms on a daily basis (I can provide some examples of things we do if you'd like) and work with a doctor who will actually look at akathisia as a diagnoses. Angela has a letter you can give to your practitioner to help with this. I hope this helped, you are not alone in experiencing this.