I just came off a (failed, unfortunately) cycle of IVF. I actually have to say that the physical process was nowhere near as hardcore as I'd anticipated, and really wasn't bad at all - obviously it can vary from woman to woman but I basically felt fine throughout and kept wondering when it was going to start being as full-on as I anticipated, and it never did.
Other people have way more experience and can probably explain this better, but what basically happens is this. First off, you'd have some investigative tests to check things like what your egg reserve is like, whether you ovulate, what your lining is like, and so on. Expect, probably, some blood tests, a transvaginal ultrasound (colloquially known as 'dildo-cam' - it's undignified but nothing worse than that) and possibly your clinic may want to do some more tests involving minor procedures, depending on your history and their protocols. (For example, I ended up having to have a hysteroscopy - basically a tiny camera up through my lady-parts for a look at my uterus. It was no big deal and actually quite interesting).
When treatment starts, you'll self-administer medications (which your clinic will teach you how to do). You may have to sniff some of your meds; you will have to do some injections. This is not as big a thing as it sounds - you're probably hearing 'injections' and thinking Trainspotting, but they're generally subcutaneous (so, under your skin, not into a vein). They are basically impossible to do wrong! I didn't find them painful at all. Some women report side effects from the medications but again, I was fine.
You'll go and have regular scans (dildo-cam again!) while you take the medication to stimulate your ovaries. This is to check how everything is going, measure the number and size of developing follicles on your ovaries, and keep an eye on the lining of your uterus. As you approach egg retrieval, you might feel some discomfort if you have lots of follicles (because basically your ovaries get way bigger than normal).
When your clinic are happy with the size of the follicles, they'll instruct you to do a timed 'trigger' injection that prompts the eggs/folicles to get ready for ovulation. They then do your egg retrieval just before you ovulate (so you don't lose the eggs). This is basically a minor surgery, done under sedation. Most women find the process itself fine (whooo sedation!) but you may be uncomfortable afterwards. It essentially involves inserting a fine needle into your ovaries (through the vaginal wall) and hoovering out the eggs. You shouldn't need an overnight stay after your egg retrieval; in fact you can probably go home within a couple of hours. Some women are at risk of a condition called OHSS at this time - basically, where the ovaries have been overstimulated - which can cause discomfort and in some cases means further treatment has to be delayed while it's resolved.
Your eggs get mixed up with your partner's sperm in a Petri dish to fertilise (or, for some couples, they use a technique called ICSI, where they basically manually fertilise the eggs by selecting sperm cells and injecting then directly into the egg). It's likely that not all will fertilise at this stage. An embryologist then monitors their progress. Depending on your clinic and the number and quality of embryos you have, they will then transfer one (possibly two, in some circumstances) back into you on either the second, third or fifth day after you egg retrieval. Again, it's likely that not all will continue to develop over this time, of that some may be much better quality than others. Embryo transfer is pretty straightforward - no worse than getting a smear test done, really, though you do have to have a full bladder which makes it a bit uncomfortable. Basically, they pass a very fine catheter through your cervix and then whoosh your embryo in through that. You'll probably then be on progesterone to help support a pregnancy establishing (this might be a pessary or suppository, an injection, or a gel). If you have surplus embryos of high enough quality, they'll be frozen so you can use them for future attempts.
And then you wait two weeks to see if it worked. The two week wait, for my money, is the worst part of the whole process because there's nothing else to do but wait. And wait. And wait. Which brings us to the other side of the equation - the emotional impact. It's really hard to say how you may react emotionally, but the whole process can definitely be a roller-coaster because it's very high-stakes. At any stage in the process, things can go awry (no eggs retrieved, or none fertilised, or none make it to transfer) so it may not be straightforward. And you're right - it may not work. Your clinic should be able to give you got personal odds of success, but it's generally more likely that a round of IVF will be unsuccessful than that it will work (and in some cases an unsuccessful outcome is very much more likely).
My advice would be, think about going and having an initial consultation. You'll get the chance to ask questions and find out about your treatment options, and you aren't committing to anything by doing so. You may decide it's not for you, and that's fair enough; or it may be a chance to start the ball rolling.
Hope that's some help...