TL;DR: You can relax - your database is absolutely secure.
The encryption used by KeePass is not broken as of today. Brute-Forcing the AES-256 key is infeasible. Assuming your password has more than about 80 bits of entropy the millions of key derivation rounds render brute-forcing the password infeasible, too.
The entropy of your password depends on how well you chose your words. Lets do another example:
You chose 5 distinct words. The attacker must assume a set of about 7000 english words to not miss one of your words.
The words alone make up for 10^19 possible combinations. Lets further assume you changed two letters per word to a number or a special character. You chose numbers similar to the letter and random special characters from a set of 10. The letter exchange alone makes up for (13 * 13)^5 = 137 * 10^9 possible combinations.
All in all, that is about 1,3 * 10^30 possible combinations; equivalent to about 100 bits of entropy.
Brute-Forcing 100 bits is not completely impossible imo (128 is considered impossible pre-quantum; but 100 to 128 is a huge step). That effort is far beyond feasible for anyone else than large governments or enterprises. Unless you are Edward Snowden (which i am sure you are not since you asked this question), no one will go through that pain.
The large number of derivation rounds add to that, even.