Sorry to hear about your slump. I was in a very similar situation a while back, and it took me a month or two to figure it all out. It sounds like after the first game, the part of the lane you're playing is drying up. The ball will either pick up too early if you throw it slower, or won't pick up at all if you throw it harder.
What I would suggest is once the oil starts to change, move quite a bit left or right to get into a new part of the lane. I would say move right (this is all assuming you're a righty) at first, and move a good 5 boards right to get away from the area you were originally playing. Try that part of the lane, and if it isn't working well, then move left of where you were originally. And if neither of those moves produce results, then it may be a mismatch of gear and you might need to look at weaker equipment, or polishing your ball up now.
To practice adjusting to lanes, what I did/do is go to open bowling after a night where there's only ONE league and then open bowling. This way you have lanes that have only a handful of games on it, enough to change the lanes from how they started, and you can really work on how to bowl during lanes that are in transition.
Good luck, and I hope everything works out well!
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Proud Supporter of Rob Stone
Obviously, you aren't a golfer.
Some stayed in the foothills, some washed logs like teeth.