Is It Advisable To Terminate The Pregnancy While On Meth Usage?

I started to use meth again, and not heavy user but after I started I got pregnant. Didn t know til about 8-10 weeks in. I stopped. Was clean for about a month. Started drinking. Was on a drinking binge for about 5 days. And smoked meth the 6th day. All in all I know worst thing to do but was going through a extremely rough situation. Anyways told my OB and requested to have an amino to get the best details on damage cuz I will terminate this pregnancy. Decided to go to rehab. So question is I have this invasive procedure on Monday at noon. Smoked about 8 hits of meth (b4 deciding to go to rehab) on Thursday night and about 4 more b4 5 pm Friday. will the fluid show high concentrations of meth? I requested this test because I told dr I had a drinking problem and used b4 I found out and will be leaving to treatment so this test is for drugs and to see how much damage I have done. I need to prepare myself if it s anything less than minimal damage. In your professional opinion should it be?