I think you need to look at your situation from your lender's eyes. They have a borrower whose account is sitting at ~60%+ utilization and the billing period isn't over. The automated online credit line increase function will likely come to the determination that you made a big purchase that you won't pay off immediately. In situations like this you have a much better chance at talking to a human.
Obviously there are a couple near term fixes:
- Spend some cash on some of your purchases, or
- Make a mid-cycle payment
Personally, I think mid-cycle payments are too much work. I don't want to log in to my credit account and make payments all the time.
If I was in your shoes, I'd assess this month's spending. Was this month a normal month or did I make some one time large purchase?
If this is my normal spending volume I'd make a mid-cycle payment of the current statement balance, then call the lender and ask the rep for a line increase. Point out your payment history. Tell them you spend everything on this card and would like to continue to do so, but you're overspending relative to your limit and that makes you uncomfortable.
If this was a one-off month with some large purchase thrown in, I'd do nothing. Your credit score only matters if you're shopping for credit. While it's important to have a good sense of your financial picture and check in on your credit periodically to ensure nothing is wrong, there's no sense in losing sleep because your unusually high utilization this month has impacted your score, it will be right back to normal next month (barring any other unforeseen unusual expenses).