Sorry to hear of the issue.
If you have a diagnosed injury from this then you could sue for personal injury, yes. But they need money to pay any claim. So you would need to know whether they have money or assets to claim against.
If there is no injury claim then you could consider a defamation claim. Though these are even more expensive and as such, it's only worth pursuing one if you know the person who defamed you has money.
A defamation claim requires that someone has either verbally said something (slander), or written something (libel) which was untrue and they knew it to be untrue - with the intention to damage your reputation. The untrue comments have to be brought to a third party’s attention to qualify.
There is a defence if the person who made the comments can prove the comments were true, or they held an honest belief their comments were true.
So there is a high evidential burden to prove defamation - meaning a lengthy court case. And the person who defamed you needs the means to pay any court judgment which is another consideration - it is all well and good to sue but ultimately if they have no money then it would be a pyrrhic victory.
You can claim for any financial loss incurred such as lost business, lots future job prospects and anything else reasonably incurred.
The limitation period is only 1 year for a defamation claim, so you should ensure you issue the claim at court within a year of the incident.
To stop further damage you need to send them a cease and desist letter.
A template “cease and desist” letter is available at this site : https://www.lawdepot.co.uk
If you click in tot the site, go to the search box and type in "cease and desist" and the choose the general letter.
The letter should say you demand that the social media posts are taken down immediately failing which you will apply for an injunction from the county court.
As for a defamation case, they are complex with them being heard in the High Court so you would be well advised to instruct a firm and ask them for a no win no fee agreement - a few do offer this so you would not have to pay anything up front.
Here are examples of law firms who could help you with this :
https://www.carter-ruck.com/expertise/reputation-media-privacy/defamation/
https://www.samuels-solicitors.co.uk/news/defamation-claims
https://www.curzongreen.co.uk/practice_areas/defamation/