I understand your frustration very well, because I was many times leaving the pool with the thought "I never want to swim again". But I always came back and I am glad I did, because now I really enjoy swimming. It is worthy persisting.
If you could swim free before somehow and now it is worse, don't worry too much about it - it works on principle one step back two forward.
It is essential that you get all the air that you need and I think balance and breathing influence each other quite a bit.
Do you breath in sweetspot or in skating turning your head? If in skating, do you have problem to get to the air or is it a rhythm?
In drills try to be very relaxed, aligned, but relaxed. You need to feel weightless and water supporting you. When you are relaxed, everything goes better. And the air is always there for you.
Sometimes, what takes you under water in spearswitch, is leadarm too deep or head positioned too low. Try to spear forward and feel your neck long and relaxed in line with spine. Try to use your whole body to spear a there should be a glide.
Bubble out very gently during the switch and then take a deep breath; if you end under water and need to get to the air take as many breaths as you need to feel fully "oxygenated" and relaxed again. Then do another switch or two.
Did you try zenskating yet? That is a great drill that improves your balance.
How much do you drill and how much do you swim? The idea of doing half lap for now sounds great. Or swim a few strokes, breath in skating, even a few times if you need, make sure you are balanced, aligned and comfortable, another few strokes, until it feels good; there are very helpful exercises on your DVDs.
And don't forget what feels good is right, swimming should never be a struggle. Try to play in water and with water and enjoy it!
Hope it helps little bit, good luck.