Brownish spotting and clots during pregnancy. What is the dark color blood with cramps?

hi, I am 7 weeks pregnant and have had moderate dark red/brownish blood spotting fairly regularly frrom week to week, I once found a couple of small clots when I wiped but the bleeding stopped. Today I had period like cramps and had a rush of blood in my pants, when i looked it was still dark red in colour but more than ive had before, it seems to be slowing down but i am concerned..I am yet to make an appointment with my doctor which I will do this week. I had icsi transfer with 2 embryos and have been rerading that this may be an indication of twins???What are the odds its twins or just a single pregnancy..I seem to be showing very soon and getting bigger at such an early stage aswell, i could really do with some advice and the facts. Thank you :)