I've done it as well.
I've learned what not to like about trainers. They do help you with motivation but only if it's a good trainer. I had four trainers in two years because they generally don't make enough money to stick with it, so you just get a good, self-motivated and knowledgable trainer who knows it... and poof, 4-6 months later they're gone. So you want to pick someone who's a career type with a good customer base. Also as others have said, level 1/2 trainers know pretty much nothing other than "stay away from those exercises that aren't 100% safe because that's what the course told me' meaning that they will put you on exercises which are relatively "safe" and not challenging for your body, and they won't push you to failure at all. My last trainer, I would have quit if I hadn't already paid for the time.
Here's my advice... go to the gym 4 days a week and establish a hard pattern that everyone knows. So they can say "gerrbear's at the gym until 6:30 so don't bother them" and you have the same routine every day that you can count on. Do a warmup of 10-20 minutes, then hit a section of your body hard - I do shoulders/tris, back/bis, legs/abs, chest/tris in that order and leave a slush day in every week where I will either rest or do 40 minutes of cardio + HITT. I do everything with intensity whether it's cardio or resistance training... not a believer in hour long cardio workouts at 40% of my capacity. Do everything hard and adjust your calorie intake rather than spending all that time burning out and bored doing halfassed cardio. Most important: get your nutrition sorted out and on point for you and your goals. It's at least as important as the training and probably more important.
Also, concentrate on compound movements. The most important ones: deadlift, squat, pull-ups, dips, rows, bench, pull-downs, standing press. I usually don't even do much arm work because I push the compound movements to or past failure (using declines or drop sets) and tire out all the supporting muscles as well, which are often arms. Isolation exercises are a waste of time if you're not a competitive bodybuilder... for example, a heavy set of back exercises should have your arms pumped and tired... do a few standing curls at the end of a back day if you feel up to it, and call it done.
And I will also echo what others have pointed out, the trainers who are on juice have no idea how to make your body improve unless you're also on juice. They have routines and body stresses that will not work for a natural body at all. Like 5x10 full failure rear squats followed by 5x10 full failure front squats, followed by 5x10 full failure deadlifts, etc. etc. that will SNAP YOUR @#$% UP if you try it without the juice. But they don't know any better.
Good luck.
