The Gorgie men looked set for a slot in next month's Parkhead final before Nick Ross grabbed a last-minute equaliser for nine-man opponents Inverness to send the game into extra-time.
John Hughes' side then claimed a 4-2 penalty shoot-out victory at Easter Road to heap fresh misery on Hearts after a year of turmoil.
But there was good news just 24 hours later when fans group the Foundation of Hearts announced that they had struck a deal with majority shareholder UBIG to take control of their 78.97 per cent stake in the Jambos.
Locke - whose side return to action for the first time since their Leith loss by taking on Inverness again at the Caledonian Stadium on Saturday - said: "I was just like any Hearts fan after the semi. The Monday, Tuesday, Wednesday - all I could feel was that sick feeling in my stomach.
"I was reliving the game again in my head time after time and all I could think about was the fact we were a minute away from a cup final.
"But there is no point looking back - there is nothing we can do about it now. What happened was a disaster for us.
"However, we have had bigger challenges to face this season with trying to make sure the club survives.
"We had a wee bit of good news the day after the game and we hope things are moving forward. The administrator Bryan Jackson came and addressed the players and it was good to hear him speak.
"We've still got a long way to go but it was really pleasing just to hear a bit of good news for a change because for most of the last four years, any time you have heard news from Hearts it hasn't been great."