Nitrofurantoin Anhydrous and stomach pain

(Nitrofurant Monohy)
I've been on this medicine for 6 days and recently have been experiencing chest pains, SHARP and intense stomach pain and my pee was light green this morning. I wasn't sure if this was a side effect or could be due to something else, but apparently some one else's posting indicated similar side effects.

I have had a UTI for 2 months, this is my 2nd antibiotic. The other one calmed my symptoms and reduced the burning and the need to pee but then it came back after about 2 weeks. I am now on 100mg of Nitro and have been for only 2 days and I am getting almost all of these symptoms. I have a headache, severe nausea, every time I use the restroom I have diarrhea, stomach pain, chills, and all of my muscles are aching like I have just been in a car accident. I feel miserable and after reading all the post here - I am calling my doctor for another drug.