Whenever you feel down, tell yourself that Hashem is capable of ANYTHING! If Hashem was able to create and maintain the world, He is able to send you your bashert!
I know plenty of people who are chubby, overweight, even obese, who have gotten married. Yes, there are some sane people out there (can you imagine?) Not everyone is only concerned with the externals. Someone will come along who is worthy of you, and won’t care how much you weigh!
As for now, do your hishtadlus by always looking put together, even if you have a few extra pounds. Don’t let yourself wally in self pity (though that does sound very tempting…)