GI said it's fine to take metoclopramide indefinitely...?

For context, I am diagnosed with Ankylosing Spondylitis and GERD.

3 weeks ago my GI doctor prescribed me Metoclopramide to "try it out", after I've been struggling with digestive issues for years, I've recently been trying to get him to get me the gastric emptying study but he refused and instead gave me these pills.

The pills work wonders, I finally feel hunger again and can eat full meals, started gaining back some weight too. It does make me feel suicidal at times, but it's still a worthwile tradeoff.

The pharmacist had a look of absolute horror on her face when she gave me the box though, she told me to not take it for more than 5 days unless specifically instructed, and to not take it for more than 12 weeks under any circumstance. So I read the booklet and some online information about the medication, and it does indeed have some pretty stark warnings.

This week I had a call with my GI doctor, I asked him how long is this safe to take? He said "You'll be fine, you're young. You can try lowering the dosage if you want." and to keep taking it for now, and scheduled another call 4 months out.

Now I'm a bit anxious, since I've read about tardive dyskinesia and it does not sound too encouraging. What are your thoughts, is he right?