Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.
Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.
You should seek immediate evaluation at your local emergency room. You will need to have a stroke workup; but also give that you have a history of MS, you should have an MRI with and without contrast. If there is an active lesion causing the MS, you would benefit from a trial of steroids at the discretion of the treating physician.
Again, I highly suggest you be evaluated ASAP. Once the evaluation is complete, you would likely require physical therapy.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.
If this happened abruptly I would seek immediate medical attention just to be on the safe side.