hair loss can be one of many things..(1) it could be something that runs in your family. you said how your dad started losing hair in his 30's..it could happen to you also, just a little bit sooner. ask your mom about men on her side of the family..(2) the hair products have nothing to do with hair loss. as long as you wash your hair and get the products out so they dont build up, itll be okay. (3) when you shampoo your hair you should try to massage your scalp. that will help circulate the blood flow in your head, and it helps with hair growth. (4) everything you put in your body (food, drinks, vitamins, medicines, etc..) comes out thru your hair, nails and skin. so maybe if you dont have as much time to eat because of your new job, try taking a multi-vitamin. there's actually a line of hair products that is for people with thinning hair/hair loss. its called Nioxin..you can find it at most hair salons. its kind of expensive, and it works best if you use the shampoo, conditioner, and the scalp treatment. the nioxin hair line has a vitamin..i take it everyday.
you also have to remember that your hair will naturally change on its own every 7 years, whether it be the color, texture, density..so that could be playing a role in your hair loss.
one other small little tip, if your hair is thinning, you should wear it a little bit shorter. trying to cover up the area that has thinned with overly long hair just makes it 10 times more noticable. <edit> there are a lot of guys who try to keep one side longer and comb it over to the other side...or take hair from the back of their head and comb it straight forward to cover up a thin area. if i were you, id consider cutting it a little bit shorter.
you could also go see your doctor and have some bloodwork done. it might be a deeper issue than what you're thinking.