Current miscarriage

On Thursday evening I had a positive pregnancy test, was very shocked as I’m only 10 weeks pp, however on Friday morning I woke to heavy bleeding and cramps, and have still got heavy bleeding. I tested today, and got a negative pregnancy test. I haven’t contacted the doctors yet, to let them know I was pregnant, but what do I do now? Do I need to be checked to ensure I’ve passed everything naturally or am I just left to deal with it myself now? From the UK