Hi Southsea - it does sound like you have a touch of the babyblues, so I also want to add my reassurance that you are doing really well.
I am going to write a mammoth message here about breastfeeding as you seem concerned about it.
Regarding expressing, if you are getting sore nipples, it will tense you up when you go to express and this will hinder the let-down reflex. Has anyone suggested a warm flannel on the breasts to help with the initial part of the expressing? You may be one of many women (like myself) who don't get much success with expressing. As for number of times a day to be expressing, I think you will get as many answers as people asked. Timing is as important in expressing replacing feeding, so you do need to be pumping very regularly to keep the stimulation going so that your supply is kept going strong. One other thing is the idea that if the breast is soft that there is not much milk there, this is not so, a full breast is nice and reassuring, but not a sign that there is "more" milk really. It is more to do with the body adjusting to times of day it expects to be used. Even an apparently "empty" breast can still provide milk to a suckling baby, unfortunately this is not true for breastpumps!!!!
Just to give an example that might help explain things a bit more. With my children I would be successfully breastfeeding for weeks..... but attach a pump and nothing would come out. If I pumped the next day at the same time, I would get a couple of drops only. If I pumped the third day, I might get a ounces or two if I was lucky. Clearly not enough to replace a feed. But the body adjusts to the times of pumping, and the stimulation of pumping does work whether or not you get anything out.
For me to pump enough to get some stored so that I could have a night out, I often pumped on one side then attached the baby to the opposite boob, the let-down on the baby side meant I would get much more than trying before attaching baby!!!! Does this make any sence to you??!!!
One thing I would be cautious off is irregular pumping, this does not allow your body to build up a natural pattern. Ideally yes you would be pumping to equate to when you would normally be feeding a baby, this with a newborn would be every two hours during the day and maybe three to four hourly at night (depending on the baby!)
Can you pump while at the hospital, just after visiting Thomas? It would be good to be pumping at times while you are there, especially to get your body used to the idea of feeds while with your baby (again I hope this makes sense to you)
But I think mostly you need to be kind to yourself too, don't let yourself get too sore, try to aim for times that don't stress you too much. If this means that you are only pumping every 4 hours day and night but getting good rest between (for body, mind anbd boobs!), then why not! Your body will adjust to a change in pattern in about 3 days, when the time comes to switching to you feeding Thomas directly. And compared to pumping, breastfeeding should feel like a doddle to you with all you are going through.
Finally, you mention a boob feeling full but not functioning well, be very careful that you do not get mastitus, warm flannel, massaging boob towards nipple to encourage flow. Watch for any red patches and or soreness, get help immediately from nurses if this happens. Do not wait for it to get worse (mistake I made twice!)
Please, please don't let this put you off trying to breastfeed. A baby is much much more effective at getting milk out of a breast, more than any pump can do! Are you being encouraged to put Thomas to the breast as often as possible without tiring him? Please be reassured that you are doing absolutely fantastically at the moment, even if the hormones are running riot on your confidence!
OK enough breastfeeding talk from me!
Folks have already given their opinions on carseat and stroller. In my humble opinion, I think would definitely get a stroller, the quality and price alone would be worth it, in addition to the using it on the journey home. As for the car seat.... they have different regulations in europe to US, but I believe that the US rules are stricter, so again, it might be worth saving a couple of pounds to buy it over there.
I hope all the passport / visa complications get sorted soon too, a headache you could do without on top of everything else.
Remember you are doing really well, and try not to let the hormones get you down too much! Will come back and check how you are doing soon.