Seller pulled out

I'm a first time buyer and got an offer accepted on a place a month ago, the day before I left for Christmas holidays. I fell in love with the place as soon as I went to see it - it hadn't really been what I was expecting to find. A flat instead of a house, but much closer to the city centre than most places I was looking at, and with a garden (a must have for me), and in an historic estate. I went in over asking with a really competitive offer (the estate agents confirmed that with me), but still got pushed for 5 extra grand even though all of the other offers were at least 10k under mine - because the sellers had already gotten an offer accepted on a house that was much more expensive, and apparently they needed the money. I was over the moon when it got accepted.

I spent a lot of my holiday getting my mortgage arranged and a solicitor, as I was told they wanted to do the deal quickly. I was then told, about 3 weeks into all of this and after I had spent my precious holiday time arranging all of this, that they had been on holiday and wanted to get their valuation and surveys done before they instructed their solicitor, so I should hold off on my arrangements for now.

One month after my offer got accepted they've decided to rescind, because the seller's got money from a family member and feels that they can afford to keep both places now. After all that hassle pushing for a best and final offer, too.

I know English homebuying is notoriously shit, and this stuff happens, but I can't help feeling a little heart broken, and so angry and bitter at this seller for messing me about as well.

For people who have been in this situation before, how do you pick yourself up again and move on without getting too dejected? It just feels so shit that sellers can be so flippant like this and get away with it scot free. And it's hard to hype yourself up to be competitive and make future offers when things like this happen.