No it's not, gut feelings are very real and often right.
I had a sudden gut feeling that my girlfriend was cheating on me, and what do you know, she did. Another girlfriend, I had that same gut feeling about her, when we break up she immediately goes to some guy friend she talked with while we were together. I'm either psychic or extremely lucky or people in general can just sense when "the honeysuckle has hit the fan".
I'd suggest to confront her directly and ask her if she wants to be with you, what she's planning to do to bring the relationship back, etc. Chances are you're not going to be happy about what she says but the GOOD things is you'll be able to cut your losses before you get fully cooked slowly and deal with a more extreme heartbreak. Trust your goddamn gut feeling it's there for a reason!
P.S. It's called a pre-emptive strike. If you're feeling she's going to dump you, dump her instead to minimize the pain. Sure you'll let her feel more shitty but a person who wants to leave their partner would be good to pay most of the emotional cost and not the one who'd really get dumped anyway.
