You haven't said anything about yourself. Do you have others, maybe children living with you? Do you work or are you at home all day? Do you like to cook, or grow things, or keep animals? The last answer must be yes.
Your water problem is easily solved. We collect rainwater in several 1000 litre barrels from every roof, large or small, that we have. That is sufficient for all our stock, ponds, and vegetable production. The water supply for our house is a well. Water to the animals from the barrels is via a series of gravity fed pipes to drinkers (the barrels are raised and the water can run uphill a bit if necessary). We have an electric pump at the lowest point to top up the supply barrels. For your septic tank - plant a reed bed or willows downhill from it, or all around if it's flat - this will take up a lot of the water and contain any contamination, and will also provide some firewood and browse for sheep or goats.
For your land, yes it can be seen as a tiny amount and you are very sensible to reassess what you can keep there. We all go through the initial over exuberance where what we have seems a huge area compared to what we had before, but land is never enough. Keeping animals can be a major financial burden and rarely gives a profit, unless you add value. This could be in the form, for example, of growing loads of fruit, veg and herbs then making jams, chutneys, cakes and so on for sale. Selling surplus eggs at the gate can help cover the purchase cost and feed for your hens, but by making cakes, lemon curd and so on, you are adding value, by adding your time and effort. You could grow flowers if you're in a suitable spot - locally grown is gaining in popularity today, as opposed to hot house flowers imported from halfway around the world.
Can I suggest that you don't make a final decision just yet? Take a year to see how much time and effort growing takes in your location, see what will grow and what will not, see what through traffic there is (for garden gate sales), see what crafts might sell (if you are crafty) and take time to work out costings for sheep or goats. I'm with you on bonding too closely to pigs to send them off, even though I grew up on a pig farm. When we kept them here we loved our two sows so much, they were intelligent and such fun. You might find the same with a small number of sheep - they are far brighter and more interesting when you keep them yourself than most people know, and are not for producing just any old slab of meat. Have you thought of goats? You can use the milk for all sorts, including soap making, and they provide the odd goatling which you can sell, or pop any males into the freezer (if you know which animals will ultimately be eaten from birth, it does make it a bit easier)
Glamping - not for me. You would have other people around all the time in the season, with an impact on your privacy, and you would not be able to use the land for anything else. You may be very gregarious and love having others sharing your little spot of Paradise, but I know I wouldn't.