It could be the stress of your separation. After 13 days o/due I'd expect a positive result. Doesn't rule out pg though. I'd see your gp on Monday to figure it out. Hope you get the result you want (although I can understand at this time that you may not even know what that is).
I'm a bit gutted if I'm honest. We weren't ttc or anything, and it's not great timing but I'm still feeling sad about the negative results. Guess I'd better sort out an appointment with the doctor if it doesn't come by Monday.
Sorry to hear you're upset. Do you think your split is final. I know it sounds trite but I'm a bit of a que sera sera (sp?) sort, and think that everything happens for a reason. I really do hope it works out for you.