Could I be autistic?

I am going through a massive change in my life. I'm in my 40s, and I'm re-evaluating everything in my life. I'm coming to the conclusion that it's possible I'm autistic and have become fairly successful at adapting to society; to an extent. What has brought me here though is that a difficult year has put strain on every area of my life and some constant traits that I've been able to hide that don't serve me well, have reared their ugly head. And I've really spiraled into a negative mindset. Some of the reasons I believe I may be are:

1. I have always, ALWAYS, felt like I didn't belong. Feelings of alienation I am aware of began in play school, and continue to this day. I feel like an alien most days; like my outer interactions bear no resemblance to my inner world. 

2. I have learnt to fit in. I have developed a script for most situations. If someone does this, I say/do this. I memorise details about people so i can ask them about it the next time. However, when a new situation is thrown my way, or someone deviates from the script, I'm caught in freeze mode. I don't react appropriately to the oitside eye and people have then seen an opening to take advantage of me. Which has happened too often to talk about.   

3. Add to this the fact that I'm completely unable to stand up for myself in most situations. I don't know why, but my voice just seems to clam up. As a result I've never been very good at drawing boundaries. I've experienced bullying, and I've had volatile relationships with two men who I've been completely bonded to. My logical mind says that I should leave, but it would be akin to sawing off my own leg. 

4. My partner of 22 years says that in gullible as I cant read people and that i never used to look him in the eye. I still find eye contact very hard, but I've worked harder to maintain it in a professional setting and with good friends. And with the reading of people, it's true. I get terrible anxiety because I have no idea if someone likes me unless they tell me. I can't read people's intentions, but I'm vey sensitive to emotions. It's painful. 

5. I'm awkward. I can be relaxed and interesting one day and next day I don't get the joke. The work banter is sometimes said in a way that I can join in, but half the time I don't know someones kidding me until they say, it's just a joke, no you're not in trouble, I'm just messing with you. 

This is just a flavour of what I feel. I'm so sick of being me right now. I've been on and off on anti depressants since i was 18, but the alienation has never gone away. I have begun thinking about whether to end my life when my youngest son is an adult. I don't like being like this.