Hi,
I am sorry you are dealing with stress over getting your medication, you don't need that on top of IVF! You definitely want to have everything you need in advance to avoid interrupting stimms if you can't get supplies immediately.
There are a couple of options -
The clinic could give you a prescription for a given quantity of Gonal F that is likely to do you for the whole cycle stating dose "as directed" ie they do not need to specify a certain dose on the script. Make your clinic aware that it could take a few days from getting the prescription to actually having the medication.
You can obtain meds with scanned/email prescriptions from EU countries at Lloyds probably other high street pharmacies too but I used Lloyds so I know for sure they do it, and there is also an online chemist called fertility2u. Either of these will probably not be able to supply the medication on the same day, either because they post it out to you from the online one, or a normal chemist would have to order it in as it is not generally kept in stock.
I would try and get this sorted asap as who knows if EU prescriptions will still be accepted after Brexit.
Alternatively if you have a sympathetic GP, you could take along any prescriptions & letters you have from the clinic, explain your situation and ask if they would do a private prescription for the outstanding Gonal F, again written "take as directed by specialist". They may or may not be willing to do this, and there will likely be a charge for it, maybe about £25.
Personally I would not be willing to start a cycle unless and until I had secured the entire stock of medication I was likely to need, as the stakes are high and consequences of running out midway and not being able to get it are dire.
Another thing worth noting is that once medications are dispensed from a chemist, if you don't end up using them they cannot be returned for a refund even if unopened.
What I did was order and pay up front for my entire batch of meds from Lloyds but agreed with them that they would keep hold of the bulk of it & I would collect it in small increments as I went on. That way you can get a refund for any surplus that has not been handed over to you.
This strategy ended up saving my daughter's life as I was on estrogen and progesterone to support the pregnancy in the first trimester, and my house was burgled & the pharmacy bag taken from my kitchen top, they were probably hoping it contained methadone or something they could sell. It took a day or so to get a new prescription emailed from Spain, but as I still had supplies sitting behind the counter at Lloyds, I could immediately get more & avoid miscarrying.
Best wishes with your cycle, I hope you get this sorted out quickly.
B x