I'm sorry you are feeling this way. I went 3 days with no cowashing, wetting or anything therefore no comb or fingers went through my hair either and when I got into the shower on the 4th day and finger combed I thought I was going to be bald when I was done! I do agree with Hippie that if you used to brush every day and now you don't it makes a HUGE difference. You will see ALOT more hairs come out in the shower, I know I do. I must lose at least 100. I think it was about 300 the day I skipped washing for so long. I know when I used sulfate poos all the time my hair was big and thick looking but now that it's a little more tame it doesn't look like that anymore. I think your hair looks absolutely lovely in all the pictures. Do you have any bald spots? I agree with everyone that if you aren't comfortable with what's going on then check more into it. I understand about the money though too. Maybe try styling your hair your "old way" with sulfate poo and your old style products and see if it looks the same. The look may be from different products also.
I hope you feel better soon.
From your pictures, it looks more like your hair is weighed down than thinning. But it's really hard to tell.
Do you wash and style daily? If you counted 100 hairs in the drain and you wash every other day, that's at the low end of normal for hair loss. Also if you're growing your hair out, the wad of hair in the shower drain after you wash will be larger because the hairs are longer.
Have you noticed any patchy spots on your scalp? Unfortunately no one on this site is qualified to give you advice if your hair is really falling out for some medical reason.
One more thing you might want to look into is traction alopecia. If you wear your hair pulled back severely, like in a tight ponytail or headband, you could experience hair loss. You can also lose hair if you part your hair exactly the same way every day.
One of the things I picked up on the most while reading how to treat hair loss is diet and nutrition. You need to make sure your diet is rich in essential fatty acids, protein and iron. Getting enough of the B vitamins is important too.
Another contribution could be stress. If you find yourself freaking out a lot, you might want to look into some deep breathing exercises you can learn or maybe try meditation. I know I mentioned lavender oil before so if you can get some, at nightime pour a couple drops into your hands and give yourself a nice relaxing scalp massage!! It'll help stimulate the hair follicles and provide circulation to get hair growing. Plus, it'll feel nice!