ANSWER - I’m always a bit sceptical about the idea of messengers from the animal kingdom being bad omens. Usually when an animal or bird goes out of its way to interact with you it is more valuable to try and work out what the symbolism means and what, if any, wisdom the animal may be trying to impart. Rationally you know this raven is incapable of making any material different to your life (unless it behaves like a seagull and decides to attack you!) so linking its appearance to your levels of luck seems a bit too tenuous a link.
It’s a shame we don’t know if the birds were ravens or crows. Ravens tend to be the bigger of the two but that’s only a useful comparison if the two birds happen to be standing side by side. I’ve had a look at birds in your local geography and ravens tend to be the more common. Ravens apparently also tend to “soar” more so if the flight you observed was more of a soar than a flap chances are the birds you saw were ravens.
Ravens are traditionally associated with being the messengers of death (so I suppose it is easy to see why they are viewed as ill omens…). However in much the same way that the Death card in the Tarot deck doesn’t mean it is time to start booking your funeral, in the same case with animal symbolism “death” does not always mean in the literal sense. Death can refer not just to the end of life but to the end of a way of life and to the new way of life that would necessarily entail.
I think the idea of self change is echoed by the bird’s flight toward you. Put literally you faced injury (if you hadn’t ducked you would have been hurt) but by your own actions you changed your fate. This fits in with the bigger picture – the association with death isn’t your own death but a death of the path you are currently treading. By making positive changes (symbolised by the ducking) you avert negativity and move forward with your life in a positive and fulfilling manner.