so I came on my period last Monday and normally my periods last 5 to 6 days. but this time it only lasted 4 days and a little bit on the 5th day so iv not bled since Thursday. last night after doing the deed with my partner I went to the toilet to find some pink discharge cleaned my self up didn't think anything off it but then this morning iv started bleeding again not like a full on period just a very light period (like the beginning of a period) why would this happen and if it is a period why would I come back on after 4 days of being off?