Me again! 
Last period started on the 4th of March and ovulation was highest between 15th and 18th March. Me and partner dtd on the 16th and 18th (no contraception) been doing a few tests here and there and one had a faint line and then last week I got a quite definite pink line. I assumed this was positive but I took one again this morning (8 days past expected AF, 2nd urination, boots own brand) and it looks negative. AF is now 8 days late, I've got very bad lower back pain, vivid dreams, sensitive nipples and full feeling in breasts with prominent purple veins and just the general feeling of being pregnant. Has anything similar happened to anyone on here? I really don't want to give up hope as want this more than anything!
any help/ advice would be greatly appreciated! X