Game started without me during my loading

So, now i just started a game.Had NO DISCONNECTS OR CONNECTION ISSUES,then when i connected i realised that game already lasts for 2,5 mins and enemy laner is lvl 3... Again, i had no connection issues, my hardware is weak,yes,and my loading speed is poor,but i loaded even a bit faster than usual and as long as i know 1st loading can go even for 5 mins(had someone with even worse pc than i do) and we still waited this person and only then game started.I find this bug a really gamebreaking and frustating to have in your games when you have weak PC.

P.S. Sry for any grammar mistakes in my thread, my english is not very good :(