Given what you wrote, it's hard to tell one way or another what they think about you personally. Was the code stored on your personal device, or a company-issued one? If it's company-issued, it's probably nothing to worry about, since, if they were to terminate you, they could immediately restrict your access to the codebase.

I view it vastly more likely that this isn't anything personal, it's just a new corporate decision to limit who has access to the code. If someone's job is a bit more complicated, but they can still do their work, while the company is far more protected, that is a good trade-off for lots of folks.

Also, your company "looking to reduce expenses" doesn't mean anything. Every company is. You will hear that, in some form or another, in almost any organization. If they have to increase spend for cybersecurity, they will.