Well last night I had a scare, went to the loo and I had some bleeding apologies for TMI but it's wasn’t red blood, just like really watery brown, almost like tinted urine, but it def is blood. My period would have been due on Monday and I'm due to HPT on Thursday morning.
Me and DH rushed to Asda last night at 11.30pm to get some tests. We were so stressed out we figured that at least if we tested we would have more information. We bought two tests and did one last night. I decided if it was negative I would accept it, but if it showed positive, I could still hold on to some hope.
Test done...................................It showed a very strong positive.
I trawled the net looking for info and found a post by an IVF nurse on another site replying to a girl in the same situation with the same symptoms, she said it sounded very much like implantation bleeding and that it is safe to test 10 days after the HCG injection as it should have cleared your system by then.
It is 16 days since my HCG injection and today would be 14 days post ET (including the day they were transferred), most girls would be testing today anyway. I'm really hoping this is a true positive.
Here's another the bit off the web:-
After ovulation the egg travels into the uterus and burrows into the lining of the uterus. For some women implantation will cause slight bleeding or spotting. This is called implantation bleeding. This is sometimes confused for an early period.
Implantation bleeding, also called implantation spotting, does not look like a regular menstrual period. Implantation bleeding is scanty and usually pink or brownish discharge.
Implantation bleeding or menstrual period? Implantation bleeding normally occurs a week to a few days before your period would normally start. Spotting that occurs around a week after ovulation is likely implantation bleeding; whereas, spotting that occurs very close to the time that your period would normally start may not be. A normal menstrual cycle generally starts off light and then gets heavier. Spotting can sometimes be the sign of an early period. If this is the case, the spotting will pick up to heavier bleeding. If you have spotting right around the time your period would normally start, it can be more confusing. You will need to take the wait and see approach or take a pregnancy test to determine
This is crazy as I had totally no intention of testing early, DH and I had discussed it and agreed that if we got a positive we wanted to feel like walking on air and any situation which would cast a shadow of a doubt was a no go. But here we are with a positive too scared to be overjoyed, really don't know what to think!
Age 33, been trying to conceive 1½ years. Husband low sperm count / motility etc. Started IVF/ICSI cycle 11th July 07. Start stimulating 10th August 07, Egg Collection Friday 24th August, Embryo Transfer Mon 27 August
So did you have any symptoms at all? I'm trying to be positive but still a little nervous even with slight cramping off and on, not sure I have felt anything I might consider implantation, though I have no clue what that might feel like... so all I can do is dream and wonder.... 
Just curious if you had any clue you were getting BFP?