Day before mothers day and I feel like the worst mom ever...

My son had been having very bad tantrums all day everyday lately and today was just a really bad day im not feeling good to begin with and I completely list my patience, he was going around touching everything he's not supposed to throwing toys at me the cat screaming to the top of his lungs throwing food on the floor which is unusual and he started screaming and then I started screaming at him I just lost it... we sat down at bedtime I held him and cried and told him I was sorry for losing my patience... I seriously feel like the worst mom ever... we are almost 80% sure he is autistic and trying to learn how to deal with his feeling and outburst has been the hardest thing I've had to do... because even if I redirect or use time out or anything he seems to just really not understand... we have an appointment at the end of this month to have him evaluated and I just hope to get answers on how to maybe handle all of this a little better so I can be better for him.