Hair has been falling out like crazy! help!

Soo.... a month or two ago i had a lot of hair. Everything was fine.. I colored and bleached it no problem there as i was taking care of it. Camping came and new shampoo tresemme botanics damage therapy i used since then .. I hate the shampoo so i stopped using like 5 days ago... And i also had to be on antibiotics for a uti. I guess i need more water in my system. I may do 1 gallon a day from now on..
But my hair has been Drastically falling out like all day.. everyday.. Not in large clumps as if it were cancer but.. strands of my hair.. falling from its roots!
Its freaking me out because im noticing how thing my hair is getting. And it is too fast!
I bleached my front hair almost rouge xmen hair but its blonde and already i can see that most of my hair i had there is now Gone! I'm freaking out cause i don't know if its internal? or if I have to much radiation around me? or not enough water or poor diet? or allergy to mold and my cat? shoot. Im freaking out here!