need help now for my friend!!!

She started spotting a couple Days ago. She is on birth control pills so she stopped taking the pill because she thought she might be pregnant. Well today she started bleeding heavier do she put a tampon in, when she went to take it out a lot of blood came out of her and when she wiped there was a clot on the toilet paper. She has not taken a test so she didn't know if she was for sure pregnant. Any advice on what this could be? Is it miscarriage or something else?