Bactrim DS and spider bite

I was checking side effects of Bactrim now for my sister. She took one pill and had reactions.

Last year my husband had side effects to Bactrim. He was taking it for a spider bite that got infected when he went to the doctor (dr. didn't properly clean hands, etc). The dr. said culture of the area wasn't necessary.

End results were extreme swelling and rash from his neck down to his feet. He was holding at least 20 pounds of fluid (we weighed him). He contacted the dr. when the rash first started, but was told to keep taking. A couple days later went to the dr. and dr. still thought he should keep taking Bactrim.

It was close to the end of med. so he stopped. It took several weeks for the rash and swelling to disappear.

Since then he has been to another dr. and told he has MRSA. We are going the natural route and it is working.

I have taken one pill of bactrim ds, also known as sulfameth/Trimethoprim 800/160. I too about lunch today for a spider bite i got the night before my leap surgical procedure so during that the doctor said he thought i had gotten THAT COMMUNITY STAFF like MRSA that 99.9 percent people have but not my body is itching all over, i have chills, and my back is burning, I feel different all around kinda like im in another world and very sleepy but cant sleep. Im not really having many emotions or feelings either,I just feel like I don't care and that is taking 1 pill at noon and 1 around 10pm. I don't no what to do I have 2 babies under 2yrs of age and I need to get better but i don't no if the med is safe.