RBT, drug driving

So this morning around 7:15 got pulled over for random breath and drug test and it came back positive for coke. This is my first offence so I have that going for me,I’m a tad bit stressed what to do. I never fully said yes to doing coke but I never said no either I kinda just went when they asked “yeah I’m not sure how that’s happened” and “I did go out on Saturday night” that’s about it. I’ve looked it up and yeah a hefty fine and obv a license suspension. Any advice ? I am on my green P’s too so can’t even apply for a work license. Should I get a lawyer ASAP or when I get the message for them summoning me to court. What to do I’m not well.