Why are my contacts making my eyes red and sting?

So I have been wearing contacts for 6 to 8 months now, so I am fairly new to contacts. Every time I use them I wash my hands really good, I put in new solution, and I make sure I use my eye drops regularly throughout the day. I haven't had a problem until just recently, and I don't even know if its my contacts or not.

I went to the Emergency a couple months ago after screaming to my mom that I couldn't open my eyes, my eyes were really red, as red as a tomato, and my eyes itched to a point where they hurt, it felt like I had thousands of little hairs in my eyes. I got to the emergency room and they told me I had Chemical Conjunctivitis. I have been sitting here thinking for the past few days what chemicals have I used differently? Have I tried anything new? I had nothing.

I went to the eye doctor and he told me not to wear my contacts for a couple weeks. A couple weeks went by, my eyes got much better, so I put my contacts back in after the eye doctors approval today. I made sure to dispose of my old contacts and put in new ones, I also washed the container to put my contacts in real good and put new solution. Now my eyes are red again, my eyes sting really bad and idk what to do.

I have soft lenses, the ones you wear for 2 weeks then dispose of them. I don't wear them while sleeping at all. I only wear them on an average of 6 hours every 4 to 5 days a week usually. I really don'y know what the problem can be. Am I allergic to the plastic or something?
Added (1). I always wash my hands before doing anything with my contacts, I make sure my solution is clean and I wash the thing to put my contacts in regularly. I am afraid I am going to go blind if I'm not doing something right.
Added (2). The eye doctor looked at my eyes and he told me under my eye lids they are rough, he said they are supposed to be smooth, but he didn't tell me much more. Does that differ from person to person? I don't know what that means.

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