If there were any lingering doubts about whether the Bitcoin bubble was over, those should be gone now. After falling below $9,000 last Thursday for the first time since November, Bitcoin has fallen south of $7,500 as of this writing. Bitcoin was trading at right around $8,250 at the start of Monday, so it's down nearly 9 percent so far today.

Bitcoin had rallied a bit over the weekend, peaking at nearly $9,500 on Saturday, but Monday's news that Lloyds Bank has prohibited its credit card customers from using their cards for cryptocurrency sent prices reeling.

“Across Lloyds Bank, Bank of Scotland, Halifax and MBNA, we do not accept credit card transactions involving the purchase of cryptocurrencies,” a Lloyds Banking Group spokesperson told MarketWatch. “It’s a case of protecting our credit card customers from the risks associated with the price volatility of cryptocurrencies."

Late in January, Capital One also barred cryptocurrency purchases with its credit cards.

Combine the skepticism of banks and regulators with an influx of new investors excited about all things cryptocurrency, and you have a recipe for a sell-off. (Even the guy who fixes my furnace and the mechanic who repairs my car both accept cryptocurrency payments.)

The heady days of skyrocketing Bitcoin prices seem like a dim memory, even though it was less than two months ago that the number was threatening to crack the $20,000 mark

Other cryptocurrencies are also seeing price drops. As of publication time, Ethereum had dropped from around $880 to $738.36 in the past 24 hours, while Bitcoin Cash was down about 17 percent during the same period.

Update (2/5, 1:30pm ET): Bitcoin is now trading below $7,000.