Use the following code to check if it works.

	<script src="//code.jquery.com/jquery-3.2.1.min.js" type="text/javascript"></script>
	<script type="text/javascript">
	$(function () {
		var currentUserEmail = _spPageContextInfo.userEmail;

		// begin work to call across network
		var requestUri = _spPageContextInfo.webAbsoluteUrl +
					  "/_api/web/Lists/getByTitle('StaffDirectory')/Items?$filter=Title eq '" + currentUserEmail + "'&$select=Section";

		// execute AJAX request
		$.ajax({
			url: requestUri,
			type: "GET",
			headers: { "ACCEPT": "application/json;odata=verbose" },
			success: function (data) {
				if(data.d.results.length>0){
					var mySection = data.d.results[0].Section;
					if(mySection!=null){
						getFileName(mySection);
					}								
				}		
			},
			error: function () {
				alert("error found");
			}
		});
	});
	function getFileName(mySection){
		// begin work to call across network
		var requestUri = _spPageContextInfo.webAbsoluteUrl +
					  "/_api/web/Lists/getByTitle('Site Pages')/Items?$filter=Section eq '" + mySection + "'&$select=FileLeafRef";

		// execute AJAX request
		$.ajax({
			url: requestUri,
			type: "GET",
			headers: { "ACCEPT": "application/json;odata=verbose" },
			success: function (data) {
				if(data.d.results.length>0){
					var CalFileName = data.d.results[0].FileLeafRef;
					alert(CalFileName);
				}		
			},
			error: function () {
				alert("Calendar not found");
			}
		});
	}
	</script>