An expensive mistake

Made such a bummer this weekend which ended up costing me a lot of money!
I was going home from London with the Eurostar on the 4th of February but ended up not being able to pass security because I had bought a ticket for the 4th of MARCH. Sh*t!!
Since I had to get back to Paris I had no other option than to by a ticket for the next one and that ended up costing me 133 euros!
I could have bought a ticket home for those money! My boyfriend actually offered to pay for it since I can't really afford something like that right now, but I insisted on me paying for it myself. That's the lesson I'll have to learn. An expensive mistake but hopefully I've learned to trippel-check (!!!) the next time I buy any kind of ticket.