I made my own bot too. It worked fine and made profits from January to July 2017. Then all alts crashed by 80%, and the bot was left with coins bought close to ATH.
I trade manually now
Looking at your curve, I take it that you don't reinvest the profits in the bot ? Otherwise I would expect an exponential shape curve, instead of linear.
Ok I see what could happen to me
Yes I do reinvest, but instead of increasing the money I put on one particular coin, I just set the bot to work on another altcoin to diversify a bit. I explain the fact that the curve stays linear due to two reasons, first these new coins are less profitable. Before chosing a new market, I test it a bit and obviously, the first ones I chose were the best (although I could be wrong). Secondly, the global market of altcoin is deteriorating. After the January crisis, all the altcoins dropped, but with a really good volume nd a lot of panic sells and fomo the dip buys, that made the conditions good enough for the bot, but now, the coins are still dropping, but the volume is not here anymore.
Only time can tell me how it goes. At the moment I let the bot run as it's still profitable