Swelling at 18weeks

Hello po! First pregnancy ko po. I'm at 18weeks, normal ba na mamaga nalang randomly/suddenly yung paa/ kamay/ legs? Di naman sya sabay sabay namamaga. Minsan yung kamay at paa lang. tas this afternoon lang yung legs. Natakot kasi ako sa nabasa ko na may possibility na sign ng preeclampsia. Baka po may alam and with same experience. Would appreciate the help po :)