So about a month ago my bike was leaking oil and it was dripping out of the front end of the bike.. I filled the bike back up with oil and the leaking has stopped ever since.. however, yesterday I was riding back from work and I noticed that at low rpms in first gear the bike would stutter and someitmes even stall, making me have to rev up to about 5k before I released the clutch slowly. Also, the bike was backfiring a bit during the stuttering. Today, I let the bike warm up for about 15 min, hopped on gave it some gas and it just turned off. Haven't been able to get it to start since, sometimes the starter will make the clicking sound but the engine won't do anything, sometimes the starter doesn't even make any sound.

what should I do/where do I start? I have almost no technical experience
Thanks alot for the help