Give me perspective

Hello fellow techs and tech assistants!

I'm at a crossroads recently. I've been working with my company for about 8M now, and love my coworkers and doctors I work with, but finances are starting to become a problem for me. While I'm blessed in having a partner that makes a substantial income in comparison to me, I still have my own bills I am responsible for, but that has become a little harder to pay with my current pay.

Transparency here, I make $18.50 hr. As a OTJ vet tech. And I was promised a raise at the 6M mark but was denied it due to the previous PM being fired. And "not making any notes of a raise at the 6m mark" so I was expected to be paid at bare minimum $19.50 per the previous PM at my 6M mark, (but obviously wasn't) and was told I'd expect at least $20 by my one year mark. but now with the denials for raise at the 6m mark, I am scared about the actual raise I will get considering the $19.50 wasn't given, so I have a hard time believing $20 will be given at my yearly review/raise.

I've been interviewing and looking at other places that have a starting pay of at least $20 and up, and have been feeling guilty about it. I'm sure it's because of my comfort with my current clinic and the people I work with and feeling icky about looking outside of my current clinic, along with the fear of being new all over again, but I was recently offered $21 starting with reasonable benefits that surpass what I have now, but for some reason I feel "tied" in a sense to my current clinic because everything outside of pay and not having a good relationship with just one dvm at my practice isn't enough to justify leaving, because they treat me well and me and my coworkers just vibe really well.

I don't know I feel silly positing this but wanted to get some perspective on this. Have you been in this situation or something similar to it? Is my fear of being somewhere else new and making it to the 90days etc a normal feeling to have? Is worry of leaving my current practice just to find out I don't fit in to this new practice valid? I'm a chronic over-thinker so anyone who could shed some advice or light on this would help me. And finally, if you have a experience similar where it did work out for you leaving what felt comfortable will you please share. And the same if it didn't work out. I would much appreciate some outside perspective.