6 years actively working out now, past 4 months I have been bulking (hard for me with a high metabolism) and it's going great. My strength has never been better...
My recommendations -
1) Ditch the personal trainer as soon as you can. Use the internet to find good workout routines (with detailed pics) and follow them.
2) Don't buy supplements. I used to buy protein but I even stopped doing that because it's basically a meal replacement. If you can go home and make a meal it's much better and you save yourself the money. Multi-vitamins and Biotin are okay as they are something you don't get enough of just from eating.
I'm taking multi-vitamins almost every day, once a day with lunch. I used to take Biotin. If you find it hard to get food in your system after a workout (when you should be feeding your muscles) then I guess it's okay to be buying protein for that reason.
3) Run before and after your workout. Works wonders. Before: Helps get you pumped and ready. After: Once you're done with the heavy lifting your muscles are filled with lactic acid. Running will help flush it through your system which will help with muscle recovery. That last part is not really proven but I learned about it from being on the Track and Field team when we used to do sprints and heavy lifting.
I'll make a personal gym guide someday, maybe with pics to show before and after results.