I have a 10 year old that was fully BF for 2 years and a 7 month old that is fully BF.
I also have a large let down and my baby used to gag alot and lose his breath. I is scary at first but they learn ways to control the flow, like pushing against the boob and now he will come off and breath and go on again.
My milk shoots out for miles and BFing outside need planning. Before I go out I put a breast pad in one side (disposable, the washable ones cant contain the amount of milk) and then keep a muslin handy to catch any spray if the baby comes off.
Always have BF pads in your bag, lanisoh ones are the best but are expensive, but tescos have a new one thats really similar and less than half the price.
When out I alway wear something that will give me some privacy like a cardigan or something. (not a maverick BFer)
I generally feed anywhere now, if cafes etc, I try to find somewhere that is a little more private if I can (but thats just me).
TBH I would not do the cinima as they are so loud and the chances of getting trouble for a baby crying are big, also some cinemas do baby friendly screenings in the day.
I would encourage you to go to a BFing group as I benifited massively from having company of experience BFing mothers.
I would stay away from expressing at this stage, I did it with my first and it caused alot of problems especially with the increased let down, I would give it another couple of months in order for the milk let down to settle some. I have never expressed for this baby and have not had the problems with engorgement.
Mostly, relax and enjoy BFing you are still in the early stages and things are hard but you have done so well to get this far, trust your baby and your body, don't let HV's or Doctors shake your faith in what you are doing. BFing is one of the most rewarding things a woman can do with her child, and the good thing is it will only get easier from now on.