Sorry tmi...when will next af be due?

[xRubyandbumpx]

Sorry for tmi but Iooking for advice came on my period 14/04/16 I'm normally only bleeding for 4 days but I bled for 2 weeks very heavy and clots iv been to the doctor and I'm having tests...2 pregnancy tests were both negative however I do feel pregnant (tired, morning sickness etc) I would normally have had my period now again as I have a 21 day cycle should I test again or is there anyway to predict when my next af will come 🙈🙈 already have 2 children and have had previous mc