Pregnant after a miscarriage

I had a early miscarriage at 5 weeks less than a month ago.. I have been trying for nearly 2 years and out of nowhere I became pregnant with my first and sadly miscarried after 5 weeks.. however 3 and half weeks later I have been feeling really tired. I decided to take a pregnancy test (actually quite a few) and its positive... The lines on the pregnancy tests are quite faint but visible.. im scared Ill miscarry again.. has anyone else had a successful pregnancy straight after an early miscarriage?? My doctor had given me the go ahead to start trying once the bleeding stopped.