My Hair Annoys Me

Good Morninggg, what a very ugly and grey day outside today. I've been awake for at least an hour, I've had breakfast and I'm going to get dressed and then head to the shops to buy some party food. When i get in however i want to have a shower straight way. My hair is killing me this morning. I have quiet thick bushy hair that's very frizzy and none of them frizz easy products work, they just make my hair much more greasy. I straighten nearly all the time and because of this my sister said she noticed my hair thinning out, i was quiet happy, id prefer thin hair to thick..but suddenly people at work started noticing too and that's when i started thinking maybe i should cut down the straightening and just stick to the natural way. When i was young, id have a shower and when id finish and my hair was still damp I'd put hair mousse in and then let it dry naturally, the results were amazinggg curls, then i had the blond highlights in and that's what started to ruin my hair, made it very dry..But even now when i put hair mousse in, my curls no longer exist now its just waves, which I'm not to keen on. What i have noticed though, is if i put hair mousse in, let it dry and then about 2hours later try and straighten it, the process takes me a mare 20 minutes, my hair feels think and looks thicker, it's got shine and it's beautiful and feels so soft. This is a very LONGGG process though to get the hair i would like daily don't you think?
Here' what my curly hair used to be like

and that was using some very cheap hair mousse which is now longer around.. now I'm older and I'm using Vo5 for my hair and its still not doing the job!

You see what i mean, my curls have died down a lot, and my hair just always feels weak..even though i use the shampoo "Elvie Repair 5 Solutions" :( It's like I'll spend an hour straightening it and by the evening it will be all wavy again, like what is the point..?
Do you guys have any suggestions on what i could do?