Did I have a miscarriage? Or is that even possible? Or my plan b? Please help

Hello ladies. So I’m here writing this because I’m concerned if I had a miscarriage.. so on Monday May 28th I had sex with my man.. he said he came inside me and we aren’t ready for a baby yet so I took a plan b pill about 30 hours later .. but are plan bs ever 100% accurate it will work? we recently had sex again on Monday ( June 4th ) and today this morning I was cramping badly and started bleeding down there.. I was super confused because I just ended my period 2 weeks ago. Today I am bleeding , lightly but some times a medium amount will come out and I am seeing blood clots, also my blood has a little odor to it.. definitely not period blood odor.. I feel a little dizzy and nauseous.. and am having cramps. what do you ladies think? I also had to throw away my undies I was wearing because they are soaked in blood.. my blood color is bright .. Please help me, I’m too scared to go to a doctor .. is it even possible to have a miscarriage so early?