Constant Nausea and Low Abdominal Pain

 I went to the doctors 5 weeks ago with a bad UTI - nausea, fever, low abdominal pain, frequent urination etc.. I was given 3 rounds of antibiotics as the first 2 didnt seem to work, the last ones I was given was TRIMETHOPRIM and was fine on those.

I finished them over 3 weeks ago and the urine infection has gone as I went back for a test - HOWEVER, i am now suffering from extreme nausea everyday, and really bad low abdominal pains which wake me up in the night.

Does anyone have any idea what this could be and if it could be related to the antibiotics? I am worried it may be a kidney infection however I have no problems with my urine or any back pain?

I have also been taking probiotics and vitamins for 2 weeks.

Don't know what happened there! The pain and for the nausea you could get an endoscopy if it's not settling there are a number of conditions that have nausea so you'd need more tests I'd say I also get these symptoms and am currently in hospital trying to get an answer for the pain but I was already diagnosed with gastroparesis when this pain started 

A lot of antibiotics can disturb your gut flora.  Probiotics can help to rebalance your gut flora but you need to take them for at least a month.  I would go back to your doctor.