Hi Meg..I'm a hairdresser.. (Mrs Crisper).. Firstly, try not to worry...If you don't have any bald patches, thats good!..People tend to forget, that for new hair to grow, the old hair needs to fall out, and it falls out from the roots, not the ends.. I personally don't think hair thickening products work that well.. but they certainly won't hurt your hair..if you've found one you like!..Just be careful when you straighten your hair.. If as you say your hairs fine... straightening could be damaging it, making the ends finer..and may be causing a little breakeage!.. which could make it feel and look a littel thiner!..Hope that helps.. good luck x