For Lonely and Lost - Reply - Me Too but fir different reasons as a partner / carer.
You sound very much like me except for the highs, I don't get those..
I am very snappy and irritable too. When like that I tend to try and do some relaxation techniques and breathing techniques.
I too avoid people and have no friends at all and do all I can to avoid the neighbours etc, which doesn't really help.
When you do find something that does help lift the mood, even slightly write what it is down, like in a little jotter or something and when it happens you will have a little bit of something to go back to when you cant think of anything else to help.
Do you attend a Bipolar Support Group?
I know that having some friends to talk to and who will not judge you and who understand the symptoms and illness you are experiencing and how it acn affect your daily life in every aspect can really help. You sound very lonely and isolated which will not help you remain well. I liked your idea of writing down little things that help , like a list of what works, something you can return to as a reminder when in need of a pick you up.
It is so important to have just 1 0r 2 friends atleast who you can confide in or share with or have a good moan to, or who can encourage you to take part in some healthy life affirming activities which will help you cope through the low periods . Bear in mind that irritability and snapping can also be a sign of hypomania which people aften don't recognise. It can also be a feature of a mixed mood , these are common, when there are some dysphoric, unpleasant angry agitated feelings creeping into a depressive mood at the same time. Best to have your treatment reasessed. to. See previous post.
Take care. let me know how you get on with making some new friends. Its sounds as essential as any other aspect of your life. Loneliness can be very hard to bear and is not necessary. If you are inadvertantly pushing people away with your mood or attitude then you need to ask for help with this and also get meds adjusted or reviewed. Have you tried counselling specific fir bipolar disorder. Have you tried explaining to people what you are dealing with so they gain further understanding and ask them not to take your snapping seriously or personally perhaps. You may also need to work realy hard on observing your own reactions and catching them in time if at all possible.
If this is not within your control with practice then some CBT counselling and treatment adjustments can help, or maybe anger management, making sure you get enough sleep, relaxation techniques, starting a new hobby, or social activity , cutting out stimulants that can increase irritability ( Particulary Caffeine and sugar ) )and interfere with much needed sleep. Make sure you eat regular meals to avoid low blood sugar caused by low carbohydrate levels which can trigger irritability further and low mood, or swings of anger amd intolerance or tearfulness and shaking.
YOu do Not need actual sugary foods to raise blood sugar as they cause too quick a rise then a sudden fall. Long acting carbs and small amounts of protein with each meal help far better and of course plenty of fruits and veg to ensure the essential minerals and vitamins.
You may already be trying all these things to help yourself, so apologies if I am suggesting things you already know about, and are implementing ,but hey , it may help someone else too to reiterate them if they read these posts. I know I too need reminding sometimes by frineds to do things even though I know it on a theoretical level.
Talking of which I must do the same now and go for a nice relaxing walk. Take care, but do let me know how you get on. I too feel very alone trying to cope with my partner's Bipolar and have to push myself to be with people. We are all in this together.
I am try to jot down things that help me too so thanks for that suggestion. I keep them in my head bit committing them to paper might have more impact and remind me and is a positive step.
Im avoiding people and have no friends as well. 
