Got two periods in a few weeks

Hi, So I got two periods a week apart. The second period was bright red blood, not the usual colour! Ive started to see other people mention this online but I didnt know if it was true. Can anyone else share more info on what they know? SHould I go to the doctor or is this something to do with the heatwave like people online are saying? Any info on anyone elses experiance would be helpful xx Thanks x