Crashed 2 times within 6 rides. Need words of encouragement please

I bought a used bike I need for work. I’ve only biked for about 3 months of my adult life 7 years ago.

Within 5 minutes of biking home, I crashed. I heard someone about to pass me, thought they were on my right so I turned to check, they were on my left and with my turn I had swerved into them and fell hard. Some big bruises but otherwise ok.

A week ago I was biking home during pretty heavy rain, probably going too fast, and tried to get up on the sidewalk from the bike lane shown in the picture (the bike lane is on the sidewalk after the turn). I fell and got a concussion (was wearing a helmet) and some bad scrapes. I don’t understand why I couldn’t make that tiny curb.

I feel like an idiot and am super embarrassed. I am an extremely cautious person and am a little weary of biking in the first place. I don’t want to really hurt myself (already a week off of work from the last accident) but clearly millions of people use biking exclusively to get places. What are not obvious things to be careful about? How to get over the fear? Thanks.