Still + preg test 4 weeks post d&c

Had my d&c Dec 4 (baby stopped growing 8.5 weeks) and I'm still getting a very, very faint positive on urine preg tests. No bleeding or signs RPOC. This was my first d&c and wondering how long it may have taken others to get a neg test? I will follow up with my GP but it's hard this time of year to coordinate appointments and of course the annoyance when you're ready for this to be behind you...