Hi xeros, welcome to TDS!
**just noticed I have written you an essay - sorry!!**
As herbavore said, feeling the ups and downs are a natural part of life. It is a misconception that depressed people are always depressed all the time - sometimes people are, but others have some days when they feel happy and can enjoy life. Sometimes this exacerbates into bipolar disorder if the highs are having a detrimental effect on your life, but that is usually more slow paced (weeks of feeling high followed by weeks of feeling down etc) and it doesn't sound like the days when you feel okay are bothering you at all - quite the opposite, so I think they are something to be celebrated and appreciated to the full.
Are you on any treatment for your depression - I don't just mean medication - I mean therapy, or some way of developing strategies to cope with the down days and hopefully eventually stop them in their tracks?
As herbavore said, it is really important how you feel when you are suicidal - if you don't want to live but you don't actually make plans, or you have reasons to not go ahead with it (protective factors such as not wanting to hurt your family) or some part of your mind recognises that thse feelings are fleeting, then although unpleasant and definitely in need of tackling through therapy or medication, it is less worrying than if you don't feel that you have any reasons to live, that things will never improve and you actively make plans. Have you told anyone that you feel like this? Do you have a safety net or a plan in place for if you reach the point where you might harm yourself?
If you feel like you might harm yourself it is really important to contact someone - a close friend, family member, phone an ambulance, go to the ER - we have a suicide thread here too for talking through your feelings which can be of great help when you feel there is no one else to talk to (however if you feel you are in immediate danger, it is important to make sure you are safe, so please do talk to someone in real-life or go to the ER).
In terms of your drugs question - there are so many different types of drugs, with a myriad range of effects, so it is quite a difficult question to answer! In general though, you are right - what goes up must come down. The drug I feel most closely mimics my good days and depressive days is MDMA (or other stimulants to a certain degree) - on it you feel really happy - but the crash (which can last from a day to a week) feels very much like depression. You feel demotivated, lethargic, sometimes guilty or angry with yourself, very low in mood, and hopeless - even though you know it is a come-down, sometimes you feel as if you will feel that way forever and you can't remember what it is like to be okay again. This is exactly what my depression is like - even though I have had many episodes now, and i should know that they do not last, in the midst of them I cannot conceive of every feeling okay again.
This is a pretty extreme come-down reaction (I used to just feel a bit out of sorts for a few days, but it steadily got worse - and this is the reason I don't take MDMA much anymore!) but in principle you are right, for most drugs, even downers such as benzodiazepines (eg Valium) or opiates (eg heroin) - when you take them, you have enjoyable effects, whatever they may be but after they wear off you bump back to reality which it can be unpleasant; you might crave the drug, you might feel angry/guilty that you got high, or you might just not feel as if life is as good as it was on the drug. It can be easy to get used to living life with the aid of chemicals and it can be very difficult for them to manage reality sober. That is partly why The Dark Side forum exists - there is a dark side to drug taking, unfortunately.
Not every drug has these effects by all means and not everyone gets "a dark side" but the up/down pattern definitely doesd exist amongst drug takers - especially those who self-medicate I feel.
