Marijuana still in my urine

I'm aggravated because I was a pretty heavy weed smoker before o was pregnant. I'm diagnosed borderline personally disorder with mood disorder severe anxiety and depression. It's worked for me better than any medication they've ever prescribed to me. But that's neither here nor there. I quit pretty much cold turkey at 4 weeks. I took 2 hits once around 7 weeks due to extreme pain in my jaw so I could sleep. 

I did my labs and Urine screen for my 12 week appointment this week and the test came back positive. Now this is probably my anxiety taking hold and logic says I have 6-7 months for them to see I actually did quit but I'm nervous for the conversations that will be had at my appointment. I miscarried my last pregnancy before this conversation could be had but I was honest and told them I did smoke and I had no intentions of smoking while pregnant. They advised me my levels would be monitored until birth to make sure they're decreasing. I'm just panicking they'll think I'm negligent although I know my facts and even if I did continue to use marijuana while pregnant I wouldn't be killing my baby. I know many people who have multiple healthy children and smoked while pregnant. I also know people who smoke cigarettes or still used opiates while pregnant and have custody of their healthy children. 

I'm mad at myself right now even though I can't control the fact that I smoked HEAVY before finding out I was pregnant. I knew it would be at least two months before it really left my system. Anyone been through this and what did your dr say about it. 

Again. If you don't smoke or really don't know anything about the topic, it's not really necessary for you to comment. 

Thanks in advance!!