Adding to a table using MVC 5, and reset Id after deleting records

I have 2 questions:

First I wrote a code to add doctors to database, at the beginning the code worked fine but after adding validation the doctor information does not added to table.. when I press add button the URL goes to: /Doctors/Save Why the data does not saved in database? And why after I pressed Add button the program does not redirect me to Add view?

In controller there Add() action is for the Add view which contains the adding form.. Save() action is for the Html.BeginForm("Save","Doctors") that is inside the Add view..

Here is my code:

public ActionResult Add()
    {  return View();
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Save(Doctor doctor)
    {
        if (!ModelState.IsValid)
        {
            var viewModel = new DoctorViewModel
            {
                Doctor = doctor

            };
            return View("Add", viewModel);
        }

      if(doctor.Id == 0) {
      _context.Doctors.Add(doctor);
      _context.SaveChanges();
      return Redirect("Add");
        }
      else
      {
          var doctorInDb = _context.Doctors.Single(c => c.Id == doctor.Id);
          doctorInDb.Name = doctor.Name;
          doctorInDb.Symbol = doctor.Symbol;
          doctorInDb.Office = doctor.Office;
          doctorInDb.Phone = doctor.Phone;
          doctorInDb.Email = doctor.Email;
          _context.SaveChanges();
          return Redirect("Add");
        }

       } 

Add view:

@model Project.ViewModels.DoctorViewModel

@{
    ViewBag.Title = "Add";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Adding a Doctor</h2>

@using (Html.BeginForm("Save", "Doctors"))
{
    <div class="form-group">

        @Html.LabelFor(m => m.Doctor.Name)
        @Html.TextBoxFor(m => m.Doctor.Name , new { @class = "form-control"})
        @Html.ValidationMessageFor(m => m.Doctor.Name)
    </div>

    <div class="form-group">

        @Html.LabelFor(m => m.Doctor.Symbol)
        @Html.TextBoxFor(m => m.Doctor.Symbol, new { @class = "form-control" })
        @Html.ValidationMessageFor(m => m.Doctor.Symbol)
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.Doctor.Phone)
        @Html.TextBoxFor(m => m.Doctor.Phone, new { @class = "form-control" })
        @Html.ValidationMessageFor(m => m.Doctor.Phone)
    </div>


    <div class="form-group">
        @Html.LabelFor(m => m.Doctor.Office)
        @Html.TextBoxFor(m => m.Doctor.Office, new { @class = "form-control" })
    </div>



    <div class="form-group">
        @Html.LabelFor(m => m.Doctor.Email)
        @Html.TextBoxFor(m => m.Doctor.Email, new { @class = "form-control" })
    </div>

    @Html.HiddenFor(m => m.Doctor.Id)
    @Html.AntiForgeryToken()
    <button type="submit" class="btn btn-primary"> <h5> Add </h5> </button>     @Html.ActionLink("Go to doctors list", "DoctorList")
}

    @section scripts{
        @Scripts.Render("~/bundles/jqueryval")

        }

Second question:

Can I reset the Id, after deleting all records from table, from the controller?

Here is my reset code:

public ActionResult Reset()
    {
        _context.PSRs.RemoveRange(_context.PSRs);

        _context.SaveChanges();
        return Redirect("PSR");
    }

Thanks!