There may be other support available to you in your area. I'd suggest something, but I don't know whereabouts you are in the world.

As for the exercise, if you're aiming to lose weight, then you should know the following things:

Losing body fat takes time. Losing body fat around the bum around (for women) can take the longest, and (for the guys) the stomach is the one that seems to take the longest. (as I'm experiencing xD I've worked out for quite a long time, but had a couple of years in which depression ruled me, I comfort-ate, and now I'm trying to undo the damage; making progress, but it takes time, patience, and determination)

You should know that cardio, while being great for losing weight, isn't the only way to help these things along. If you add strength-training into it as well, it'll help. As I understand it, it's a matter of building muscle (which explains why I was always so thin) for which your body burns more calories to maintain. It improves your metabolism, which is what burns the calories, even while you're sitting at the computer. It's worth doing some research into this stuff.

The sort of exercises you could do depend on your current physical state, possibly your gender, and with that, your aim. If you want to tone up a bit, I believe you don't want to go for too high a weight, but also, not too low, unless you just want definition. As a general rule, as I've been told by a qualified fitness instructor (step-mother xD): lower weights but more reps means definition/toning, but higher weights and less reps means bigger muscles.

Diet is incredibly important. If you aren't getting decent results, it could be down to your diet, stress, and/or bad sleep. Make sure not to neglect the fats; the media tells you they are all super evil, but it's apparently wrong. There are two "healthy" that I recommend you at least try to keep around the RDA, or whatever you need. (a dietician or something could really help, if you're able to get that) The two "healthy" fats are monounsaturated fats and polyunsaturated fats. The link should be helpful. Avoid saturated fats; they are the bad ones. Unless you're bulking for a lot of muscle growth, avoid eating too much things like red meat. You can find all sorts of resources online for what you should and shouldn't eat; I'm sure some of it will vary.

Remember, if you decide to gain muscle, it weighs more than body fat, so don't panic if you gain a bit of weight; it's the weight that's awesome to have, because it's that GRRR muscle weight. You'll know the body fat is coming off because you'll see the difference. If you're going for toning, the same may happen, but likely at a much lower amount, as you're not necessarily focusing no building muscle, but "upgrading" what you have, I guess you could say. xD

There's lots more, but Google is your friend. This is just some of the stuff I've learned over the years, from both researching online, and talking to those who are very knowledgeable in this area, such as my step-mother and her brother, both also into fitness and have frequented gyms for years. Speaking of gyms, you can do all this stuff from home. An exercise bike is just fine; I have one and have had excellent results from it. There's lots of exercises done with just a floor, a few with leaning on something, and there's even a pullup bar for your door frames. Lots of choices.

I should also point out that you cannot (apparently) lose weight in a targeted manner, for example: doing tons of situps won't lose belly fat anymore than doing a bunch of bicep curls will lose fat around that area.

Hope that helps. 8)

You should be proud of yourself for keeping up with this biking thing! Maybe you should sit and write/type out a list of the things you like about the world; things you find beautiful or captivating/inspiring. Plenty to live for, it's just that some people get so blinded by various sources of pain, that they no longer see it. Take a look outside... do you see birds, do you feel the wind on your skin, do you hear all the noises of life around you? Those are just some of the things I consider wonderful, if you just really look and listen, feel, smell, and touch. I used to think life wasn't worth living, but I was wrong... even with all the crap in the world, there's always something beautiful.