Reaction to 4 week slow release medication? Possible TMI. What to do?

[homeontherange]

I've NC as I have friends on MN and this post makes me easily identifiable.
Apologies for the length of this post, I don't want to drip feed.

I have ongoing right side ovarian cysts, the pain has been so bad I was admitted to hospital recently.
Whilst there the gynecologist prescribed Decapeptyl 3mg dose injected every 4 weeks for 3 doses.
So far I have had one dose.

The Decapeptyl will stop my ovaries working, if this treatment is successful by stopping the cysts and pain occurring, the plan is to have one or both ovaries removed.

I was expecting menopausal side effects and possibly a 'pain surge' in the first two weeks after treatment.
The gynecologist thinks I have been peri menopausal for 2 years before these injections, I'm 42.

The injection was given last Saturday morning, on Tuesday evening I started to get stomach cramps and diarrhea along with the ovarian pain I was already experiencing.
For 5 days now I have had diarrhea and cramps with some nausea.
My temperature isn't raised so I have no reason to think that it is a bug or something I've eaten.

I am taking Dioralyte but I don't want to take Immodium or any of the analgesics I have been prescribed that could cause constipation as I don't want to stop it from flushing out of my system.

I am keeping well hydrated but I'm unable to eat much at all and the pain I was already experiencing has surged and now I have stomach cramps and diarrhea too.
This cannot be helping to improve my condition.

If the Decapeptyl and the dose lasts for 4 weeks assuming this is causing the diarrhea will it be another 3 weeks before it stops?

Is there anything that I can do?
The pain is excruciating.