for one day I dared to believe we'd finally done it

I feel so sad today. I'm on my second cycle of clomid and was due to start AF on friday. I'd felt strange all week, I had brown cm last weekend and sharp pains all week in different places to the normal AF cramps. I did a clearblue easy test yesterday morning and it came up with a very faint line, I have never seen any type of second line so rushed upstairs where husband had a look and said he could see it too. (it's still there today) it was blue and beautiful. I did another cheap sainsbury's test in the afternoon and again there was a very very faint line. I spent yesterday feeling incredible. I really dared to believe after 20 months we'd finally done it. This morning though I did another test to see if the line was stronger (actually did a clearblue digi) and it came up negative. My AF has now arrived with avengance and I feel so sad and useless. I hate my body and I hate pregnancy tests. Could it have been a chemical pregnancy? Could Clomid have been affecting the results?