Is 1800 mg of ibuprofen a day okay???

Yes it is safe if your Podiatrist told you to take it, I take 600 mg ibuprofen 3 x daily which is exactly what you are being told along with tramadol. I have been doing it for decades. try drinking some milk to settle your stomach. Other than that if the milk does not help I would call your doctor again.

That's a lot of ibuprofen to take, I think that I would ask for a different solution to the problem from him also your body is telling you that it doesn't like that amount either. So I would tell your doctor about the side effects that your getting from taking so much also.

From the good guys/girls here: https://www.drugs.com/ibuprofen.html

"Do not take more than your recommended dose. An ibuprofen overdose can damage your stomach or intestines. The maximum dosage for adults is 800 milligrams per dose or 3200 mg per day (4 maximum doses). Use only the smallest amount of ibuprofen needed to get relief from your pain, swelling, or fever".

The problem is the nausea and stomach cramps which would indicate using a different prescription anti-inflammatory medication as you cannot tolerate that dose of Ibuprofen.