Exercising and Gaining Weight - Help :(

Hi,

I am sure this topic has been discussed over and over again at various stages but i am reaching out as I am at a wits end.

I have been exercising for the last few months and have been eating well. I don't starve myself but don't take food as a luxury either. However i have been gaining weight. Not sure what to do and advice would be much appreciated.

My routine since March this year has been:
1. Bicycle to and from work 4 days per week: 14km round trip. To work is fairly easy but the way back is a steady hill for 6.5 kms.
2. I have taken but running again and try to run to work once a week. I admit i have been half-assed about it in March / April but now doing it twice a week: 6.5km each time. At a comfortable pace of 6.35 min/km. I am focussing on making sure i run comfortably as I am training for my first 10k.
3. On the weekends i take a SLOW walk over a couple of hours and cover 14km.

Food:
Usually averaging around 1400 calories per day. Some weeks i have an average deficit of 400 calories per day other weeks its maintenance but still under by about 200 calories.

I put on weight late last year as I was enjoying too many glasses of wine after work. I have not had a drink since March (except for two occasions for a work function).

No fast foods or sodas. My splurge consists of a plate of home made pasta or a handful of rice. Usually diet is gluten free . cereals, non-diary milk, protein, healthy curries etc. Only cheats are a biscuit or two twice a week.

The issue:
Normally i would continue and try to mix things up a bit. but considering that i use pedal power / run commute to work and eat, I have been expecting to lose weight. But i am gaining which is not good especially as I am going on a two week beach holiday with my boyfriends and expect him to propose (maybe) and want to look good in a bikini. Unfortunately i look horrible and need some way to lose the extra flab which i seem to be putting on for whatever reason and hence DESPERATE for advice and would appreciate any insight.

I have a jelly belly and jelly butt - so frustrating :(

My current weight: 59.4kg / 131 lbs.
Height; 5'34 / 163cm